diff --git a/.yamllint.yml b/.yamllint.yml
index baed83012b..c18c17fe43 100644
--- a/.yamllint.yml
+++ b/.yamllint.yml
@@ -3,3 +3,6 @@ extends: default
 rules:
   line-length:
     max: 120
+  indentation:
+    # See https://github.com/yaml/pyyaml/issues/545 for why
+    indent-sequences: false
diff --git a/src/schema/README.md b/src/schema/README.md
index 10a177ae0d..948d687a52 100644
--- a/src/schema/README.md
+++ b/src/schema/README.md
@@ -9,57 +9,144 @@ Any changes to the specification should be mirrored in the schema.
 
 ## The format of the schema
 
-The schema reflects the files and objects in the specification, as well as
-associations between these objects. Here is a list of the files and subfolders
-of the schema, roughly in order of importance:
-
--   `datatypes/*.yaml`: Data types supported by the specification. Each datatype
-    may support many suffixes. These suffixes are divided into groups based on
-    what extensions and entities are allowed for each. Data types correspond to
-    subfolders (for example, `anat`, `func`) in the BIDS structure.
-
--   `entities.yaml`: A list of entities (key/value pairs in folder and
-    filenames) with associated descriptions and formatting rules. The order of
-    the entities in the file determines the order in which entities must appear
-    in filenames.
-
--   `top_level_files.yaml`: Modality-agnostic files stored at the top level of a
-    BIDS dataset. The schema specifies whether these files are required or
-    optional, as well as acceptable extensions for each.
-
--   `modalities.yaml`: Modalities supported by the specification, along with a
-    list of associated data types. Modalities are not reflected directly in the
-    BIDS structure, but data types are modality-specific.
-
--   `associated_data.yaml`: Folders that are commonly contained within the same
-    folder as a BIDS dataset, but which do not follow the BIDS structure
-    internally, such as `code` or `sourcedata`. The schema specifies which
-    folders are accepted and whether they are required or optional.
-
--   `suffixes/*.yaml`: Suffixes supported by the specification.
-    Each suffix schema file contains, at minimum, `name` and `description`
-    fields. Additionally, it may have a `unit` field defining possible
-    units for data associated with that suffix, as well as fields
-    defining the range or types of values which are allowed for the data,
-    such as `minValue` and `maxValue`.
-
--   `metadata/*.yaml`: Valid fields for sidecar metadata json files.
-    These files contain, at minimum, the following fields: `name`,
-    `description`, and a set of fields for describing the field's data type.
-
-    The data types include `type`, which MUST have a value of
-    `array`, `string`, `integer`, `number`, `object`, or `boolean`.
-    There are additional fields which may define rules that apply to a given
-    type.
-
-    -   `array`: If `type` is `array`, then there MUST be an `items` field at
-        the same level as `type`. `items` describes the data type and rules that
-        apply to the individual items in the array. The same rules that apply to
-        describing data types for the field itself apply to `items`.
-        Additionally, there may be any of the following fields at the same level
-        as `type`: `minItems`, `maxItems`.
-        Here is an example of a field that MUST have three `integer` items:
-        ```yaml
+The schema is divided into two parts: the object definitions and the rules.
+
+The object definitions (files in `objects/`) describe attributes of individual
+objects or data types in the specification.
+Common information in these files includes full names, descriptions, and
+constraints on valid values.
+These files **do not** describe how objects of different types
+(for example file suffixes and file entities) interact with one another, or
+whether objects are required in a given dataset or file.
+
+The rules (files in `rules/`) describe how objects related to one another,
+as well as their requirement levels.
+
+## Object files
+
+The types of objects currently supported in the schema are:
+
+-   modalities,
+-   datatypes,
+-   entities,
+-   suffixes,
+-   metadata,
+-   top-level files,
+-   and non-BIDS associated folders.
+
+Each of these object types has a single file in the `objects/` folder.
+
+-   `modalities.yaml`: The modalities, or types of technology, used to acquire data in a BIDS dataset.
+    These modalities are not reflected directly in the specification.
+    For example, while both fMRI and DWI data are acquired with an MRI,
+    in a BIDS dataset they are stored in different folders reflecting the two different `datatypes`.
+
+-   `datatypes.yaml`: Data types supported by the specification.
+    The only information provided in the file is:
+
+    1.  a full list of valid BIDS datatypes
+    1.  each datatype's full name
+    1.  a free text description of the datatype.
+
+-   `entities.yaml`: Entities (key/value pairs in folder and filenames).
+
+-   `metadata.yaml`: All valid metadata fields that are explicitly supported in BIDS sidecar JSON files.
+
+-   `suffixes.yaml`: Valid file suffixes.
+
+-   `top_level_files.yaml`: Valid top-level files which may appear in a BIDS dataset.
+
+-   `associated_data.yaml`: Folders that may appear within a dataset folder without following BIDS rules.
+
+### `modalities.yaml`
+
+This file contains a dictionary in which each modality is defined.
+Keys are modality abbreviations (for example, `mri` for magnetic resonance imaging),
+and each associated value is a dictionary with two keys: `name` and `description`.
+
+The `name` field is the full name of the modality.
+The `description` field is a freeform description of the modality.
+
+### `datatypes.yaml`
+
+This file contains a dictionary in which each datatype is defined.
+Keys are the folder names associated with each datatype (for example, `anat` for anatomical MRI),
+and each associated value is a dictionary with two keys: `name` and `description`.
+
+The `name` field is the full name of the datatype.
+The `description` field is a freeform description of the datatype.
+
+### `entities.yaml`
+
+This file contains a dictionary in which each entity (key/value pair in filenames) is defined.
+Keys are long-form versions of the entities, which are distinct from both the entities as
+they appear in filenames _and_ their full names.
+For example, the key for the "Contrast Enhancing Agent" entity, which appears in filenames as `ce-<label>`,
+is `ceagent`.
+These keys are also the recommended variable names for their associated entities in BIDS-compliant code,
+since many entities (such as `ce`) have very short filename elements.
+Each key's associated value is a dictionary with five keys:
+
+-   `name`,
+-   `entity`,
+-   `description`,
+-   `type`,
+-   and either `format` or `enum`.
+
+The `name` field is the full name of the entity. For example, the `name` for `ceagent` is "Contrast Enhancing Agent".
+
+The `entity` field is the entity as it appears in filenames. For example, the `entity` for `ceagent` is `ce`.
+
+The `description` field is a freeform description of the entity.
+The description should apply to _all_ uses of the entity,
+so if there is some additional information about the entity that applies specifically to a subset of suffixes or datatypes,
+then that information should be provided in the specification, rather than the schema.
+
+The `type` field defines the representation type for the value associated with the entity.
+Given that all entities appear in filenames, they should all be strings and the `type` field should always be `string`.
+This is true of both alphanumeric entities (such as `acq-desc`) and numeric ones (such as `run-1`).
+
+The `format` field defines the specific format the value should take.
+Entities are broadly divided into either `label` or `index` types.
+
+When `format` is `index`, then the entity's associated value should be a non-zero integer, optionally with leading zeros.
+For example, `run` should have an index, so a valid key-value pair in a filename would be `run-01`.
+
+When `format` is `label`, then the value should be an alphanumeric string.
+Beyond limitations on which characters are allowed, labels have few restrictions.
+For example, `acq` should have a label, so a valid key-value pair might be `acq-someLabel`.
+
+For a small number of entities, only certain labels are allowed.
+In those cases, instead of a `format` field, there will be an `enum` field, which will provide a list of allowed values.
+
+### `metadata.yaml`
+
+This file contains definitions for all metadata fields (fields which may appear in sidecar JSON files)
+currently supported in BIDS.
+
+Entries in this file contain, at minimum, the following fields: `name`,
+`description`, and a set of fields for describing the field's data type.
+
+The data types include:
+
+-   `type`, which MUST have a value of `array`,
+-   `string`,
+-   `integer`,
+-   `number`,
+-   `object`,
+-   or `boolean`.
+
+There are additional fields which may define rules that apply to a given type.
+
+-   `array`: If `type` is `array`, then there MUST be an `items` field at
+    the same level as `type`. `items` describes the data type and rules that
+    apply to the individual items in the array. The same rules that apply to
+    describing data types for the field itself apply to `items`.
+    Additionally, there may be any of the following fields at the same level
+    as `type`: `minItems`, `maxItems`.
+    Here is an example of a field that MUST have three `integer` items:
+    ```yaml
+    ExampleField:
         name: ExampleField
         description: |
             The description of "ExampleField".
@@ -68,49 +155,62 @@ of the schema, roughly in order of importance:
         maxItems: 3
         items:
             type: integer
-        ```
+    ```
+
+-   `string`: If `type` is `string`, then there MAY be any of the following
+    fields at the same level as `type`: `pattern`, `format`, and `enum`.
+
+    -   `pattern` defines a regular expression for valid string names.
+
+    -   `format` defines the format for the string at the same level as `type`.
+        Valid values for `format` include:
 
-    -   `string`: If `type` is `string`, then there MAY be any of the following
-        fields at the same level as `type`: `pattern`, `format`, and `enum`.
-        `pattern` defines a regular expression for valid string names.
-        `format` defines the format for the string at the same level as `type`.
-        Valid values for `format` include: `uri` (uniform resource
-        identifiers), `date` (date-times), `unit` (standard units),
-        `dataset_relative` (relative paths from dataset root),
-        `participant_relative` (relative paths from participant folder).
-        `enum` defines a list of valid values for the field.
+       -   `uri` (uniform resource identifiers),
+
+       -   `date` (date-times),
+
+       -   `unit` (standard units),
+
+       -   `dataset_relative` (relative paths from dataset root),
+
+       -   `participant_relative` (relative paths from participant folder).
+
+    -   `enum` defines a list of valid values for the field.
         The minimum string length (`minLength`) defaults to 1.
         Here is an example of a field with a restricted set of possible values:
         ```yaml
-        name: ExampleField
-        description: |
-            The description of "ExampleField".
-        type: string
-        enum:
-            - PossibleValue1
-            - PossibleValue2
+        ExampleField:
+            name: ExampleField
+            description: |
+                The description of "ExampleField".
+            type: string
+            enum:
+                - PossibleValue1
+                - PossibleValue2
         ```
 
-    -   `integer`: If `type` is `integer`, then there MAY be any of the
-        following fields at the same level as `type`: `unit`,
-        `minimum` (inclusive minimum), `maximum` (inclusive maximum),
-        `exclusiveMinimum`, `exclusiveMaximum`.
-        Here is an example of a field with a minimum value of 0:
-        ```yaml
+-   `integer`: If `type` is `integer`, then there MAY be any of the
+    following fields at the same level as `type`: `unit`,
+    `minimum` (inclusive minimum), `maximum` (inclusive maximum),
+    `exclusiveMinimum`, `exclusiveMaximum`.
+    Here is an example of a field with a minimum value of 0:
+    ```yaml
+    ExampleField:
         name: ExampleField
         description: |
             The description of "ExampleField".
         type: integer
         minimum: 0
-        ```
+    ```
 
-    -   `number`: If `type` is `number`, then there MAY be any of the following
-        fields at the same level as `type`: `unit`,
-        `minimum` (inclusive minimum), `maximum` (inclusive maximum),
-        `exclusiveMinimum`, `exclusiveMaximum`.
-        Here is an example of a field with a minimum of 0, in units of
-        kilometers per second:
-        ```yaml
+-   `number`: If `type` is `number`, then there MAY be any of the following
+    fields at the same level as `type`: `unit`,
+    `minimum` (inclusive minimum), `maximum` (inclusive maximum),
+    `exclusiveMinimum`, `exclusiveMaximum`.
+    Here is an example of a field with a minimum of 0, in units of
+    kilometers per second:
+    ```yaml
+    ExampleField:
         name: ExampleField
         description: |
             The description of "ExampleField".
@@ -119,18 +219,19 @@ of the schema, roughly in order of importance:
         # k stands for "kilo", m stands for "meter", "/" means "per", and
         # s stands for "seconds"
         unit: km/s
-        ```
+    ```
 
-    -   `object`: If `type` is `object`, then there MAY be any of the following
-        fields at the same level as `type`: `additionalProperties`,
-        `properties`.
-        Objects are defined as sets of key/value pairs.
-        Keys MUST be strings, while values may have specific attributes,
-        which is what `additionalProperties` describes.
-        Here is an example of a field which MUST be an object,
-        with one optional field named "OptionalField" that MUST be a `string`
-        and any number of additional optional fields that MUST be `number`s.
-        ```yaml
+-   `object`: If `type` is `object`, then there MAY be any of the following
+    fields at the same level as `type`: `additionalProperties`,
+    `properties`.
+    Objects are defined as sets of key/value pairs.
+    Keys MUST be strings, while values may have specific attributes,
+    which is what `additionalProperties` describes.
+    Here is an example of a field which MUST be an object,
+    with one optional field named "OptionalField" that MUST be a `string`
+    and any number of additional optional fields that MUST be `number`s.
+    ```yaml
+    ExampleField:
         name: ExampleField
         description: |
             The description of "ExampleField".
@@ -140,61 +241,64 @@ of the schema, roughly in order of importance:
                 type: string
         additionalProperties:
             type: number
-        ```
+    ```
 
-    -   `boolean`: If `type` is `boolean`, then the field's value MUST be one
-        of: `true`, `false`. Here is an example:
-        ```yaml
+-   `boolean`: If `type` is `boolean`, then the field's value MUST be one
+    of: `true`, `false`. Here is an example:
+    ```yaml
+    ExampleField:
         name: ExampleField
         description: |
             The description of "ExampleField".
         type: boolean
-        ```
+    ```
 
-    Additionally, if multiple data types are possible for a given field
-    (for example, if a field may be a `number` or an `array` of `number`s),
-    then an `anyOf` field MUST be used, in which an array of data type
-    descriptions MUST be defined.
-    Here is an example of one such case:
-    ```yaml
+Additionally, if multiple data types are possible for a given field
+(for example, if a field may be a `number` or an `array` of `number`s),
+then an `anyOf` field MUST be used, in which an array of data type
+descriptions MUST be defined.
+Here is an example of one such case:
+```yaml
+ExampleField:
     name: ExampleField
     description: |
         The description of "ExampleField".
     anyOf:
         - type: number
         - type: array
-          items:
+            items:
             type: number
-    ```
+```
 
-    Finally, if the data type description of a field is reused across fields,
-    then it may be defined in a separate file and referenced in the field's YAML
-    file, with the `$ref` keyword.
-    Here is an example of a field definition using `$ref`:
-    ```yaml
+Finally, if the data type description of a field is reused across fields,
+then it may be defined in a separate field and referenced in each target field with the `$ref` keyword.
+Here is an example of a field definition using `$ref`:
+```yaml
+ExampleField:
     name: ExampleField
     description: |
         The description of "ExampleField".
-    $ref: _ReferenceFile.yaml
-    ```
-    The target file (`_ReferenceFile.yaml` in this case) MUST be located in
-    the same folder as the metadata YAML file, and MUST contain all information
-    that would be used to describe the field's data type otherwise.
+    $ref: _ReferenceField
+```
+The target field (`_ReferenceField` in this case) MUST be located in
+the metadata YAML file, and MUST contain all information
+that would be used to describe the field's data type otherwise.
 
-    Here is an example of a reference file:
-    ```yaml
-    name: _ReferenceFile
+Here is an example of a reference field:
+```yaml
+_ReferenceField:
+    name: _ReferenceField
     description: |
-        Description of "_ReferenceFile".
+        Description of "_ReferenceField".
     type: string
     enum:
         - PossibleValue1
         - PossibleValue2
-    ```
+```
 
-    The result of including `$ref` makes the `ExampleField` above equivalent
-    to the following format:
-    ```yaml
+The result of including `$ref` makes the `ExampleField` above equivalent to the following format:
+```yaml
+ExampleField:
     name: ExampleField
     description: |
         The description of "ExampleField".
@@ -202,4 +306,150 @@ of the schema, roughly in order of importance:
     enum:
         - PossibleValue1
         - PossibleValue2
-    ```
+```
+
+### `suffixes.yaml`
+
+This file contains a dictionary in which each suffix is defined.
+Keys are the suffixes (for example, `T1w` for a T1-weighted image),
+and each associated value is a dictionary with three keys: `name`, `description`, and (optionally) `unit`.
+
+The `name` field is the full name of the suffix.
+The `description` field is a freeform description of the type of data stored in files with the suffix.
+
+The `unit` field describes units in which the data may appear.
+When no `unit` field is present, data with that suffix is assumed to be in arbitrary units.
+The `unit` field may use an `anyOf` keyword if multiple valid units are possible.
+
+These entries may also, rarely, include fields defining the range or types of values that are valid for
+files with the suffix.
+For example, `MTRmap` files must have values between 0 and 100, since they represent percentages.
+
+### `top_level_files.yaml`
+
+This file contains a dictionary in which each top-level file is defined.
+Keys are the filenames (without file extensions),
+and each associated value is a dictionary with two keys: `name` and `description`.
+
+The `name` field is the full name of the file.
+The `description` field is a freeform description of the file.
+
+### `associated_data.yaml`
+
+This file contains a dictionary in which each non-BIDS folder is defined.
+Keys are folder names, and each associated value is a dictionary with two keys: `name` and `description`.
+
+The `name` field is the full name of the folder.
+The `description` field is a freeform description of the folder.
+
+## Rule files
+
+The files in the `rules/` folder are less standardized than the files in `objects/`,
+because rules governing how different object types interact in a valid dataset are more variable
+than the object definitions.
+
+-   `modalities.yaml`: This file simply groups `datatypes` under their associated modality.
+
+-   `datatypes/*.yaml`: Files in the `datatypes` folder contain information about valid filenames within a given datatype.
+    Specifically, each datatype's YAML file contains a list of dictionaries.
+    Each dictionary contains a list of suffixes, entities, and file extensions which may constitute a valid BIDS filename.
+
+-   `entities.yaml`: This file simply defines the order in which entities, when present, MUST appear in filenames.
+
+-   `top_level_files.yaml`: Requirement levels and valid file extensions of top-level files.
+
+-   `associated_data.yaml`: Requirement levels of associated non-BIDS folders.
+
+### `modalities.yaml`
+
+This file contains a dictionary in which each key is a modality abbreviation and the value is a dictionary with one key: `datatypes`.
+The `datatypes` dictionary contains a list of datatypes that fall under that modality.
+
+### `datatypes/*.yaml`
+
+The files in this folder are currently the least standardized of any part of the schema.
+
+Each file corresponds to a single `datatype`.
+Within the file is a list of dictionaries.
+Each dictionary corresponds to a group of suffixes that have the same rules regarding filenames.
+
+The dictionaries have three keys: `suffixes`, `extensions`, and `entities`.
+
+The `suffixes` entry is a list of file suffixes for which all of the extensions in the `extensions` entry
+and all of the entity rules in the `entities` entry apply.
+
+The `extensions` entry is a list of valid file extensions.
+
+The `entities` entry is a dictionary in which the keys are entity names and the values are whether the entity is
+required or optional for that suffix.
+Any entities that are not present in this dictionary are not allowed in files with any of the suffixes in the group.
+
+**NOTE**: The order in which entities appear in these dictionaries does not reflect how they should appear in filenames.
+That information is present in `rules/entities.yaml`.
+
+As an example, let us look at part of `func.yaml`:
+
+```yaml
+- suffixes:
+    - bold
+    - cbv
+    - sbref
+  extensions:
+    - .nii.gz
+    - .nii
+    - .json
+  entities:
+    subject: required
+    session: optional
+    task: required
+    acquisition: optional
+    ceagent: optional
+    reconstruction: optional
+    direction: optional
+    run: optional
+    echo: optional
+    part: optional
+
+# Phase (deprecated)
+- suffixes:
+    - phase  # deprecated
+  extensions:
+    - .nii.gz
+    - .nii
+    - .json
+  entities:
+    subject: required
+    session: optional
+    task: required
+    acquisition: optional
+    ceagent: optional
+    reconstruction: optional
+    direction: optional
+    run: optional
+    echo: optional
+```
+
+In this case, the first group has three suffixes: `bold`, `cbv`, and `sbref`.
+The second group has one suffix: `phase`.
+While the valid extensions are the same for both groups (`.nii.gz`, `.nii`, and `.json`), the entities are not.
+
+Specifically, files with the `phase` suffix may not have a `part` entity,
+while this is an option for files with the `bold`, `cbv`, or `sbref` suffixes.
+
+### `entities.yaml`
+
+This file contains a list of entities in the order in which they must appear in filenames.
+
+### `top_level_files.yaml`
+
+This file contains a dictionary in which each key is a top-level file and the value is a dictionary with two keys:
+`required` and `extensions`.
+The `required` entry contains a boolean value (true or false) to indicate if that top-level file is required for BIDS datasets or not.
+The `extensions` entry contains a list of valid file extensions for the file.
+
+In cases where there is a data file and a metadata file, the `.json` extension for metadata file is included.
+
+### `associated_data.yaml`
+
+This file contains a dictionary in which each key is a folder and the value is a dictionary with one key: `required`.
+The `required` entry contains a boolean value to indicate if that folder is required for BIDS datasets or not.
diff --git a/src/schema/associated_data.yaml b/src/schema/associated_data.yaml
deleted file mode 100644
index b54ca34fb2..0000000000
--- a/src/schema/associated_data.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-- code/:
-    - required: false
-- derivatives/:
-    - required: false
-- sourcedata/:
-    - required: false
-- stimuli/:
-    - required: false
diff --git a/src/schema/metadata/Acknowledgements.yaml b/src/schema/metadata/Acknowledgements.yaml
deleted file mode 100644
index 8eca91ab24..0000000000
--- a/src/schema/metadata/Acknowledgements.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Acknowledgements
-description: |
-  Text acknowledging contributions of individuals or institutions beyond
-  those listed in Authors or Funding.
-type: string
diff --git a/src/schema/metadata/AcquisitionDuration.yaml b/src/schema/metadata/AcquisitionDuration.yaml
deleted file mode 100644
index ab1881b09b..0000000000
--- a/src/schema/metadata/AcquisitionDuration.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: AcquisitionDuration
-description: |
-  Duration (in seconds) of volume acquisition.
-  Corresponds to DICOM Tag 0018, 9073 `Acquisition Duration`.
-  This field is mutually exclusive with RepetitionTime.
-type: number
-exclusiveMinimum: 0
-unit: s
diff --git a/src/schema/metadata/AcquisitionMode.yaml b/src/schema/metadata/AcquisitionMode.yaml
deleted file mode 100644
index ee6e1f822d..0000000000
--- a/src/schema/metadata/AcquisitionMode.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: AcquisitionMode
-description: |
-  Type of acquisition of the PET data (for example, `"list mode"`).
-type: string
diff --git a/src/schema/metadata/AcquisitionVoxelSize.yaml b/src/schema/metadata/AcquisitionVoxelSize.yaml
deleted file mode 100644
index 91c3b59f07..0000000000
--- a/src/schema/metadata/AcquisitionVoxelSize.yaml
+++ /dev/null
@@ -1,16 +0,0 @@
----
-name: AcquisitionVoxelSize
-description: |
-  An array of numbers with a length of 3, in millimeters.
-  This parameter denotes the original acquisition voxel size,
-  excluding any inter-slice gaps and before any interpolation or resampling
-  within reconstruction or image processing.
-  Any point spread function effects, for example due to T2-blurring,
-  that would decrease the effective resolution are not considered here.
-type: array
-minItems: 3
-maxItems: 3
-items:
-  type: number
-  exclusiveMinimum: 0
-  unit: mm
diff --git a/src/schema/metadata/Anaesthesia.yaml b/src/schema/metadata/Anaesthesia.yaml
deleted file mode 100644
index 29e6c2091a..0000000000
--- a/src/schema/metadata/Anaesthesia.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Anaesthesia
-description: |
-  Details of anaesthesia used, if any.
-type: string
diff --git a/src/schema/metadata/AnalyticalApproach.yaml b/src/schema/metadata/AnalyticalApproach.yaml
deleted file mode 100644
index 7c4a78f21d..0000000000
--- a/src/schema/metadata/AnalyticalApproach.yaml
+++ /dev/null
@@ -1,14 +0,0 @@
----
-name: AnalyticalApproach
-description: |
-  Methodology or methodologies used to analyse the `GeneticLevel`.
-  Values MUST be taken from the
-  [database of Genotypes and Phenotypes
-  (dbGaP)](https://www.ncbi.nlm.nih.gov/gap/advanced)
-  under /Study/Molecular Data Type (for example, SNP Genotypes (Array) or
-  Methylation (CpG).
-anyOf:
-  - type: string
-  - type: array
-    items:
-      type: string
diff --git a/src/schema/metadata/AnatomicalLandmarkCoordinateSystem.yaml b/src/schema/metadata/AnatomicalLandmarkCoordinateSystem.yaml
deleted file mode 100644
index c8dbaf4649..0000000000
--- a/src/schema/metadata/AnatomicalLandmarkCoordinateSystem.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
----
-name: AnatomicalLandmarkCoordinateSystem
-description: |
-  Defines the coordinate system for the anatomical landmarks.
-  See [Appendix VIII](/99-appendices/08-coordinate-systems.html)
-  for a list of restricted keywords for coordinate systems.
-  If `"Other"`, provide definition of the coordinate system in
-  `AnatomicalLandmarkCoordinateSystemDescription`.
-anyOf:
-  - $ref: _MEGCoordSys.yaml
-  - $ref: _EEGCoordSys.yaml
-  - $ref: _StandardTemplateCoordSys.yaml
-  - $ref: _StandardTemplateDeprecatedCoordSys.yaml
diff --git a/src/schema/metadata/AnatomicalLandmarkCoordinateSystemDescription.yaml b/src/schema/metadata/AnatomicalLandmarkCoordinateSystemDescription.yaml
deleted file mode 100644
index a9e1708e34..0000000000
--- a/src/schema/metadata/AnatomicalLandmarkCoordinateSystemDescription.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: AnatomicalLandmarkCoordinateSystemDescription
-description: |
-  Free-form text description of the coordinate system.
-  May also include a link to a documentation page or paper describing the
-  system in greater detail.
-type: string
diff --git a/src/schema/metadata/AnatomicalLandmarkCoordinateUnits.yaml b/src/schema/metadata/AnatomicalLandmarkCoordinateUnits.yaml
deleted file mode 100644
index 1a811a94da..0000000000
--- a/src/schema/metadata/AnatomicalLandmarkCoordinateUnits.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: AnatomicalLandmarkCoordinateUnits
-description: |
-  Units of the coordinates of `AnatomicalLandmarkCoordinateSystem`.
-  MUST be `"m"`, `"cm"`, or `"mm"`.
-type: string
-enum:
-  - m
-  - mm
-  - cm
-  - n/a
diff --git a/src/schema/metadata/AnatomicalLandmarkCoordinates.yaml b/src/schema/metadata/AnatomicalLandmarkCoordinates.yaml
deleted file mode 100644
index 847ec9b0d6..0000000000
--- a/src/schema/metadata/AnatomicalLandmarkCoordinates.yaml
+++ /dev/null
@@ -1,16 +0,0 @@
----
-name: AnatomicalLandmarkCoordinates
-description: |
-  Key:value pairs of the labels and 3-D digitized locations of anatomical landmarks,
-  interpreted following the `AnatomicalLandmarkCoordinateSystem`
-  (for example, `{"NAS": [12.7,21.3,13.9], "LPA": [5.2,11.3,9.6],
-  "RPA": [20.2,11.3,9.1]}`.
-  Each array MUST contain three numeric values corresponding to x, y, and z
-  axis of the coordinate system in that exact order.
-type: object
-additionalProperties:
-  type: array
-  items:
-    type: number
-  minItems: 3
-  maxItems: 3
diff --git a/src/schema/metadata/AnatomicalLandmarkCoordinates_mri.yaml b/src/schema/metadata/AnatomicalLandmarkCoordinates_mri.yaml
deleted file mode 100644
index b1435c8d86..0000000000
--- a/src/schema/metadata/AnatomicalLandmarkCoordinates_mri.yaml
+++ /dev/null
@@ -1,18 +0,0 @@
----
-name: AnatomicalLandmarkCoordinates
-description: |
-  Key:value pairs of any number of additional anatomical landmarks and their
-  coordinates in voxel units (where first voxel has index 0,0,0)
-  relative to the associated anatomical MRI
-  (for example, `{"AC": [127,119,149], "PC": [128,93,141],
-  "IH": [131,114,206]}`, or `{"NAS": [127,213,139], "LPA": [52,113,96],
-  "RPA": [202,113,91]}`).
-  Each array MUST contain three numeric values corresponding to x, y, and z
-  axis of the coordinate system in that exact order.
-type: object
-additionalProperties:
-  type: array
-  items:
-    type: number
-  minItems: 3
-  maxItems: 3
diff --git a/src/schema/metadata/ArterialSpinLabelingType.yaml b/src/schema/metadata/ArterialSpinLabelingType.yaml
deleted file mode 100644
index b49ba0cb04..0000000000
--- a/src/schema/metadata/ArterialSpinLabelingType.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: ArterialSpinLabelingType
-description: |
-  `"CASL"`, `"PCASL"`, `"PASL"`.
-type: string
-enum:
-  - CASL
-  - PCASL
-  - PASL
diff --git a/src/schema/metadata/AssociatedEmptyRoom.yaml b/src/schema/metadata/AssociatedEmptyRoom.yaml
deleted file mode 100644
index 344d4c925b..0000000000
--- a/src/schema/metadata/AssociatedEmptyRoom.yaml
+++ /dev/null
@@ -1,17 +0,0 @@
----
-name: AssociatedEmptyRoom
-description: |
-  Relative path in BIDS folder structure to empty-room file associated with
-  the subject’s MEG recording.
-  The path needs to use forward slashes instead of backward slashes
-  (for example,
-  "sub-emptyroom/ses-/meg/sub-emptyroom_ses-_task-noise_run-_meg.ds").
-# TODO: Address/evaluate mismatch between validator and specification.
-# Validator says array, specification says string.
-anyOf:
-  - type: array
-    items:
-      type: string
-      format: dataset_relative
-  - type: string
-    format: dataset_relative
diff --git a/src/schema/metadata/Atlas.yaml b/src/schema/metadata/Atlas.yaml
deleted file mode 100644
index bfe6c0ebee..0000000000
--- a/src/schema/metadata/Atlas.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Atlas
-description: |
-  Which atlas (if any) was used to generate the mask.
-type: string
diff --git a/src/schema/metadata/AttenuationCorrection.yaml b/src/schema/metadata/AttenuationCorrection.yaml
deleted file mode 100644
index 7a9e2a1ec9..0000000000
--- a/src/schema/metadata/AttenuationCorrection.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: AttenuationCorrection
-description: |
-  Short description of the attenuation correction method used.
-type: string
diff --git a/src/schema/metadata/AttenuationCorrectionMethodReference.yaml b/src/schema/metadata/AttenuationCorrectionMethodReference.yaml
deleted file mode 100644
index 5fefd7e79d..0000000000
--- a/src/schema/metadata/AttenuationCorrectionMethodReference.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: AttenuationCorrectionMethodReference
-description: |
-  Reference paper for the attenuation correction method used.
-type: string
diff --git a/src/schema/metadata/Authors.yaml b/src/schema/metadata/Authors.yaml
deleted file mode 100644
index db925e1dbb..0000000000
--- a/src/schema/metadata/Authors.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Authors
-description: |
-  List of individuals who contributed to the creation/curation of the dataset.
-type: array
-items:
-  type: string
diff --git a/src/schema/metadata/B0FieldIdentifier.yaml b/src/schema/metadata/B0FieldIdentifier.yaml
deleted file mode 100644
index 8470d3b0ef..0000000000
--- a/src/schema/metadata/B0FieldIdentifier.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
----
-name: B0FieldIdentifier
-description: |
-  The presence of this key states that this particular 3D or 4D image MAY be
-  used for fieldmap estimation purposes.
-  The `B0FieldIdentifier` MUST be a unique string within one participant's tree,
-  shared only by the images meant to be used as inputs for the estimation of a
-  particular instance of the *B<sub>0</sub> field* estimation.
-  It is RECOMMENDED to derive this identifier from DICOM Tags, for example,
-  DICOM tag 0018, 1030 `Protocol Name`, or DICOM tag 0018, 0024 `Sequence Name`
-  when the former is not defined (for example, in GE devices.)
-type: string
-format: participant_relative
diff --git a/src/schema/metadata/B0FieldSource.yaml b/src/schema/metadata/B0FieldSource.yaml
deleted file mode 100644
index e615585b8c..0000000000
--- a/src/schema/metadata/B0FieldSource.yaml
+++ /dev/null
@@ -1,16 +0,0 @@
----
-name: B0FieldSource
-description: |
-  At least one existing `B0FieldIdentifier` defined by other images in the
-  participant's tree.
-  This field states the *B<sub>0</sub> field* estimation designated by the
-  `B0FieldIdentifier` that may be used to correct the dataset for distortions
-  caused by B<sub>0</sub> inhomogeneities.
-  `B0FieldSource` and `B0FieldIdentifier` are mutually exclusive.
-anyOf:
-  - type: string
-    format: participant_relative
-  - type: array
-    items:
-      type: string
-      format: participant_relative
diff --git a/src/schema/metadata/BIDSVersion.yaml b/src/schema/metadata/BIDSVersion.yaml
deleted file mode 100644
index 00598f9d71..0000000000
--- a/src/schema/metadata/BIDSVersion.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: BIDSVersion
-description: |
-  The version of the BIDS standard that was used.
-type: string
diff --git a/src/schema/metadata/BackgroundSuppression.yaml b/src/schema/metadata/BackgroundSuppression.yaml
deleted file mode 100644
index c1178ac03f..0000000000
--- a/src/schema/metadata/BackgroundSuppression.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: BackgroundSuppression
-description: |
-  Boolean indicating if background suppression is used.
-type: boolean
diff --git a/src/schema/metadata/BackgroundSuppressionNumberPulses.yaml b/src/schema/metadata/BackgroundSuppressionNumberPulses.yaml
deleted file mode 100644
index 6507608100..0000000000
--- a/src/schema/metadata/BackgroundSuppressionNumberPulses.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: BackgroundSuppressionNumberPulses
-description: |
-  The number of background suppression pulses used.
-  Note that this excludes any effect of background suppression pulses applied
-  before the labeling.
-# TODO: Determine if this should be an integer.
-type: number
-minimum: 0
diff --git a/src/schema/metadata/BackgroundSuppressionPulseTime.yaml b/src/schema/metadata/BackgroundSuppressionPulseTime.yaml
deleted file mode 100644
index 76d3a3817d..0000000000
--- a/src/schema/metadata/BackgroundSuppressionPulseTime.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
----
-name: BackgroundSuppressionPulseTime
-description: |
-  Array of numbers containing timing, in seconds,
-  of the background suppression pulses with respect to the start of the
-  labeling.
-  In case of multi-PLD with different background suppression pulse times,
-  only the pulse time of the first PLD should be defined.
-type: array
-items:
-  type: number
-  minimum: 0
-  unit: s
diff --git a/src/schema/metadata/BasedOn.yaml b/src/schema/metadata/BasedOn.yaml
deleted file mode 100644
index 0de44ee622..0000000000
--- a/src/schema/metadata/BasedOn.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: BasedOn
-description: |
-  List of files in a file collection to generate the map.
-  Fieldmaps are also listed, if involved in the processing.
-anyOf:
-  - type: string
-    format: participant_relative
-  - type: array
-    items:
-      type: string
-      format: participant_relative
diff --git a/src/schema/metadata/BloodDensity.yaml b/src/schema/metadata/BloodDensity.yaml
deleted file mode 100644
index 41f797f9a4..0000000000
--- a/src/schema/metadata/BloodDensity.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: BloodDensity
-description: |
-  Measured blood density. Unit of blood density should be in `"g/mL"`.
-type: number
-unit: g/mL
diff --git a/src/schema/metadata/BodyPart.yaml b/src/schema/metadata/BodyPart.yaml
deleted file mode 100644
index ce6743ae0f..0000000000
--- a/src/schema/metadata/BodyPart.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: BodyPart
-description: |
-  Body part of the organ / body region scanned.
-  Corresponds to DICOM Tag 0018, 0015 `Body Part Examined`.
-type: string
diff --git a/src/schema/metadata/BolusCutOffDelayTime.yaml b/src/schema/metadata/BolusCutOffDelayTime.yaml
deleted file mode 100644
index fa3002d7af..0000000000
--- a/src/schema/metadata/BolusCutOffDelayTime.yaml
+++ /dev/null
@@ -1,20 +0,0 @@
----
-name: BolusCutOffDelayTime
-description: |
-  Duration between the end of the labeling and the start of the bolus cut-off
-  saturation pulse(s), in seconds.
-  This can be a number or array of numbers, of which the values must be
-  non-negative and monotonically increasing, depending on the number of bolus
-  cut-off saturation pulses.
-  For Q2TIPS, only the values for the first and last bolus cut-off saturation
-  pulses are provided.
-  Based on DICOM Tag 0018, 925F `ASL Bolus Cut-off Delay Time`.
-anyOf:
-  - type: number
-    minimum: 0
-    unit: s
-  - type: array
-    items:
-      type: number
-      unit: s
-      minimum: 0
diff --git a/src/schema/metadata/BolusCutOffFlag.yaml b/src/schema/metadata/BolusCutOffFlag.yaml
deleted file mode 100644
index df253736fb..0000000000
--- a/src/schema/metadata/BolusCutOffFlag.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: BolusCutOffFlag
-description: |
-  Boolean indicating if a bolus cut-off technique is used.
-  Corresponds to DICOM Tag 0018, 925C `ASL Bolus Cut-off Flag`.
-type: boolean
diff --git a/src/schema/metadata/BolusCutOffTechnique.yaml b/src/schema/metadata/BolusCutOffTechnique.yaml
deleted file mode 100644
index 6458177485..0000000000
--- a/src/schema/metadata/BolusCutOffTechnique.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: BolusCutOffTechnique
-description: |
-  Name of the technique used, for example `"Q2TIPS"`, `"QUIPSS"`, `"QUIPSSII"`.
-  Corresponds to DICOM Tag 0018, 925E `ASL Bolus Cut-off Technique`.
-type: string
diff --git a/src/schema/metadata/BrainLocation.yaml b/src/schema/metadata/BrainLocation.yaml
deleted file mode 100644
index 6a6b040cb7..0000000000
--- a/src/schema/metadata/BrainLocation.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: BrainLocation
-description: |
-  Refers to the location in space of the `TissueOrigin`.
-  Values may be an MNI coordinate,
-  a label taken from the
-  [Allen Brain Atlas](https://atlas.brain-map.org/atlas?atlas=265297125&plate=\
-  112360888&structure=4392&x=40348.15104166667&y=46928.75&zoom=-7&resolution=\
-  206.60&z=3),
-  or layer to refer to layer-specific gene expression,
-  which can also tie up with laminar fMRI.
-type: string
diff --git a/src/schema/metadata/CASLType.yaml b/src/schema/metadata/CASLType.yaml
deleted file mode 100644
index b7ddc52fee..0000000000
--- a/src/schema/metadata/CASLType.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: CASLType
-description: |
-  Describes if a separate coil is used for labeling:
-  `"single-coil"` or `"double-coil"`.
-type: string
-enum:
-  - single-coil
-  - double-coil
diff --git a/src/schema/metadata/CapManufacturer.yaml b/src/schema/metadata/CapManufacturer.yaml
deleted file mode 100644
index 1b5d3d29d8..0000000000
--- a/src/schema/metadata/CapManufacturer.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: CapManufacturer
-description: |
-  Name of the cap manufacturer (for example, `"EasyCap"`).
-type: string
diff --git a/src/schema/metadata/CapManufacturersModelName.yaml b/src/schema/metadata/CapManufacturersModelName.yaml
deleted file mode 100644
index cefe2ec06c..0000000000
--- a/src/schema/metadata/CapManufacturersModelName.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: CapManufacturersModelName
-description: |
-  Manufacturer's designation of the EEG cap model
-  (for example, `"actiCAP 64 Ch Standard-2"`).
-type: string
diff --git a/src/schema/metadata/CellType.yaml b/src/schema/metadata/CellType.yaml
deleted file mode 100644
index 7b67347924..0000000000
--- a/src/schema/metadata/CellType.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: CellType
-description: |
-  Describes the type of cell analyzed.
-  Values SHOULD come from the
-  [cell ontology](http://obofoundry.org/ontology/cl.html).
-type: string
diff --git a/src/schema/metadata/Code.yaml b/src/schema/metadata/Code.yaml
deleted file mode 100644
index 95ea9cc2fc..0000000000
--- a/src/schema/metadata/Code.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: Code
-description: |
-  [URI](/02-common-principles.html#uniform-resource-indicator)
-  of the code used to present the stimuli.
-  Persistent identifiers such as DOIs are preferred.
-  If multiple versions of code may be hosted at the same location,
-  revision-specific URIs are recommended.
-type: string
-format: uri
diff --git a/src/schema/metadata/CogAtlasID.yaml b/src/schema/metadata/CogAtlasID.yaml
deleted file mode 100644
index 556cc6d72a..0000000000
--- a/src/schema/metadata/CogAtlasID.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: CogAtlasID
-description: |
-  [URI](/02-common-principles.html#uniform-resource-indicator)
-  of the corresponding [Cognitive Atlas](https://www.cognitiveatlas.org/)
-  Task term.
-type: string
-format: uri
diff --git a/src/schema/metadata/CogPOID.yaml b/src/schema/metadata/CogPOID.yaml
deleted file mode 100644
index 7eb469e24b..0000000000
--- a/src/schema/metadata/CogPOID.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: CogPOID
-description: |
-  [URI](/02-common-principles.html#uniform-resource-indicator)
-  of the corresponding [CogPO](http://www.cogpo.org/) term.
-type: string
-format: uri
diff --git a/src/schema/metadata/CoilCombinationMethod.yaml b/src/schema/metadata/CoilCombinationMethod.yaml
deleted file mode 100644
index 39a482c720..0000000000
--- a/src/schema/metadata/CoilCombinationMethod.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: CoilCombinationMethod
-description: |
-  Almost all fMRI studies using phased-array coils use root-sum-of-squares
-  (rSOS) combination, but other methods exist.
-  The image reconstruction is changed by the coil combination method
-  (as for the matrix coil mode above),
-  so anything non-standard should be reported.
-type: string
diff --git a/src/schema/metadata/Columns.yaml b/src/schema/metadata/Columns.yaml
deleted file mode 100644
index 525ef17017..0000000000
--- a/src/schema/metadata/Columns.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Columns
-description: |
-  Names of columns in file.
-type: array
-items:
-  type: string
diff --git a/src/schema/metadata/ContinuousHeadLocalization.yaml b/src/schema/metadata/ContinuousHeadLocalization.yaml
deleted file mode 100644
index 4b4519fdf8..0000000000
--- a/src/schema/metadata/ContinuousHeadLocalization.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: ContinuousHeadLocalization
-description: |
-  `true` or `false` value indicating whether continuous head localisation
-  was performed.
-type: boolean
diff --git a/src/schema/metadata/ContrastBolusIngredient.yaml b/src/schema/metadata/ContrastBolusIngredient.yaml
deleted file mode 100644
index 5109ccd929..0000000000
--- a/src/schema/metadata/ContrastBolusIngredient.yaml
+++ /dev/null
@@ -1,14 +0,0 @@
----
-name: ContrastBolusIngredient
-description: |
-  Active ingredient of agent.
-  Values MUST be one of: `"IODINE"`, `"GADOLINIUM"`, `"CARBON DIOXIDE"`,
-  `"BARIUM"`, `"XENON"`.
-  Corresponds to DICOM Tag 0018, 1048 `Contrast/Bolus Ingredient`.
-type: string
-enum:
-  - IODINE
-  - GADOLINIUM
-  - CARBON DIOXIDE
-  - BARIUM
-  - XENON
diff --git a/src/schema/metadata/DCOffsetCorrection.yaml b/src/schema/metadata/DCOffsetCorrection.yaml
deleted file mode 100644
index 9d0245f2a2..0000000000
--- a/src/schema/metadata/DCOffsetCorrection.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: DCOffsetCorrection
-description: |
-  A description of the method (if any) used to correct for a DC offset.
-  If the method used was subtracting the mean value for each channel,
-  use "mean".
-type: string
diff --git a/src/schema/metadata/DatasetDOI.yaml b/src/schema/metadata/DatasetDOI.yaml
deleted file mode 100644
index ca9f03c7b8..0000000000
--- a/src/schema/metadata/DatasetDOI.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: DatasetDOI
-description: |
-  The Digital Object Identifier of the dataset (not the corresponding paper).
-  DOIs SHOULD be expressed as a valid
-  [URI](/02-common-principles.html#uniform-resource-indicator);
-  bare DOIs such as `10.0.2.3/dfjj.10` are
-  [DEPRECATED](/02-common-principles.html#definitions).
-type: string
-format: uri
diff --git a/src/schema/metadata/DatasetType.yaml b/src/schema/metadata/DatasetType.yaml
deleted file mode 100644
index 9f2a04f76d..0000000000
--- a/src/schema/metadata/DatasetType.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: DatasetType
-description: |
-  The interpretation of the dataset.
-  MUST be one of `"raw"` or `"derivative"`.
-  For backwards compatibility, the default value is `"raw"`.
-type: string
-enum:
-  - raw
-  - derivative
diff --git a/src/schema/metadata/DecayCorrectionFactor.yaml b/src/schema/metadata/DecayCorrectionFactor.yaml
deleted file mode 100644
index 2540a2de58..0000000000
--- a/src/schema/metadata/DecayCorrectionFactor.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: DecayCorrectionFactor
-description: |
-  Decay correction factor for each frame.
-type: array
-items:
-  type: number
diff --git a/src/schema/metadata/DelayAfterTrigger.yaml b/src/schema/metadata/DelayAfterTrigger.yaml
deleted file mode 100644
index 9fa886d84f..0000000000
--- a/src/schema/metadata/DelayAfterTrigger.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: DelayAfterTrigger
-description: |
-  Duration (in seconds) from trigger delivery to scan onset.
-  This delay is commonly caused by adjustments and loading times.
-  This specification is entirely independent of
-  `NumberOfVolumesDiscardedByScanner` or `NumberOfVolumesDiscardedByUser`,
-  as the delay precedes the acquisition.
-type: number
-unit: s
diff --git a/src/schema/metadata/DelayTime.yaml b/src/schema/metadata/DelayTime.yaml
deleted file mode 100644
index 090c459a54..0000000000
--- a/src/schema/metadata/DelayTime.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
----
-name: DelayTime
-description: |
-  User specified time (in seconds) to delay the acquisition of data for the
-  following volume.
-  If the field is not present it is assumed to be set to zero.
-  Corresponds to Siemens CSA header field `lDelayTimeInTR`.
-  This field is REQUIRED for sparse sequences using the `RepetitionTime` field
-  that do not have the `SliceTiming` field set to allowed for accurate
-  calculation of "acquisition time".
-  This field is mutually exclusive with `VolumeTiming`.
-type: number
-unit: s
diff --git a/src/schema/metadata/Density.yaml b/src/schema/metadata/Density.yaml
deleted file mode 100644
index 1ca5a4ccab..0000000000
--- a/src/schema/metadata/Density.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: Density
-description: |
-  Specifies the interpretation of the density keyword.
-  If an object is used, then the keys should be values for the ``den`` entity
-  and values should be descriptions of those ``den`` values.
-anyOf:
-  - type: string
-  - type: object
-    additionalProperties:
-      type: string
diff --git a/src/schema/metadata/Description.yaml b/src/schema/metadata/Description.yaml
deleted file mode 100644
index c7fcff62c4..0000000000
--- a/src/schema/metadata/Description.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Description
-description: |
-  Free-form natural language description.
-type: string
diff --git a/src/schema/metadata/DeviceSerialNumber.yaml b/src/schema/metadata/DeviceSerialNumber.yaml
deleted file mode 100644
index 0fad3b57b9..0000000000
--- a/src/schema/metadata/DeviceSerialNumber.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: DeviceSerialNumber
-description: |
-  The serial number of the equipment that produced the measurements.
-  A pseudonym can also be used to prevent the equipment from being
-  identifiable, so long as each pseudonym is unique within the dataset.
-type: string
diff --git a/src/schema/metadata/DewarPosition.yaml b/src/schema/metadata/DewarPosition.yaml
deleted file mode 100644
index efcfa4b6c0..0000000000
--- a/src/schema/metadata/DewarPosition.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: DewarPosition
-description: |
-  Position of the dewar during the MEG scan:
-  `"upright"`, `"supine"` or `"degrees"` of angle from vertical:
-  for example on CTF systems, `"upright=15°, supine=90°"`.
-type: string
diff --git a/src/schema/metadata/DigitizedHeadPoints.yaml b/src/schema/metadata/DigitizedHeadPoints.yaml
deleted file mode 100644
index fe6833aec7..0000000000
--- a/src/schema/metadata/DigitizedHeadPoints.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: DigitizedHeadPoints
-description: |
-  `true` or `false` value indicating whether head points outlining the
-  scalp/face surface are contained within this recording.
-type: boolean
diff --git a/src/schema/metadata/DigitizedHeadPointsCoordinateSystem.yaml b/src/schema/metadata/DigitizedHeadPointsCoordinateSystem.yaml
deleted file mode 100644
index 12aae5a548..0000000000
--- a/src/schema/metadata/DigitizedHeadPointsCoordinateSystem.yaml
+++ /dev/null
@@ -1,14 +0,0 @@
----
-name: DigitizedHeadPointsCoordinateSystem
-description: |
-  Defines the coordinate system for the digitized head points.
-  See
-  [Appendix VIII](/99-appendices/08-coordinate-systems.html)
-  for a list of restricted keywords for coordinate systems.
-  If `"Other"`, provide definition of the coordinate system in
-  `DigitizedHeadPointsCoordinateSystemDescription`.
-anyOf:
-  - $ref: _MEGCoordSys.yaml
-  - $ref: _EEGCoordSys.yaml
-  - $ref: _StandardTemplateCoordSys.yaml
-  - $ref: _StandardTemplateDeprecatedCoordSys.yaml
diff --git a/src/schema/metadata/DigitizedHeadPointsCoordinateSystemDescription.yaml b/src/schema/metadata/DigitizedHeadPointsCoordinateSystemDescription.yaml
deleted file mode 100644
index 7f34114d23..0000000000
--- a/src/schema/metadata/DigitizedHeadPointsCoordinateSystemDescription.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: DigitizedHeadPointsCoordinateSystemDescription
-description: |
-  Free-form text description of the coordinate system.
-  May also include a link to a documentation page or paper describing the
-  system in greater detail.
-type: string
diff --git a/src/schema/metadata/DigitizedHeadPointsCoordinateUnits.yaml b/src/schema/metadata/DigitizedHeadPointsCoordinateUnits.yaml
deleted file mode 100644
index d0bb682397..0000000000
--- a/src/schema/metadata/DigitizedHeadPointsCoordinateUnits.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: DigitizedHeadPointsCoordinateUnits
-description: |
-  Units of the coordinates of `DigitizedHeadPointsCoordinateSystem`.
-  MUST be `"m"`, `"cm"`, or `"mm"`.
-type: string
-enum:
-  - m
-  - mm
-  - cm
-  - n/a
diff --git a/src/schema/metadata/DigitizedLandmarks.yaml b/src/schema/metadata/DigitizedLandmarks.yaml
deleted file mode 100644
index 3276e90726..0000000000
--- a/src/schema/metadata/DigitizedLandmarks.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: DigitizedLandmarks
-description: |
-  `true` or `false` value indicating whether anatomical landmark points
-  (fiducials) are contained within this recording.
-type: boolean
diff --git a/src/schema/metadata/DispersionConstant.yaml b/src/schema/metadata/DispersionConstant.yaml
deleted file mode 100644
index 65dfb65242..0000000000
--- a/src/schema/metadata/DispersionConstant.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: DispersionConstant
-description: |
-  External dispersion time constant resulting from tubing in default unit
-  seconds.
-type: number
-unit: s
diff --git a/src/schema/metadata/DispersionCorrected.yaml b/src/schema/metadata/DispersionCorrected.yaml
deleted file mode 100644
index 68d08da8f4..0000000000
--- a/src/schema/metadata/DispersionCorrected.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: DispersionCorrected
-description: |
-  Boolean flag specifying whether the blood data have been dispersion-corrected.
-  NOTE: not customary for manual samples, and hence should be set to `false`.
-type: boolean
diff --git a/src/schema/metadata/DoseCalibrationFactor.yaml b/src/schema/metadata/DoseCalibrationFactor.yaml
deleted file mode 100644
index d4e3eaaab2..0000000000
--- a/src/schema/metadata/DoseCalibrationFactor.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: DoseCalibrationFactor
-description: |
-  Multiplication factor used to transform raw data (in counts/sec) to meaningful unit (Bq/ml).
-  Corresponds to DICOM Tag 0054, 1322 `Dose Calibration Factor`.
-type: number
diff --git a/src/schema/metadata/DwellTime.yaml b/src/schema/metadata/DwellTime.yaml
deleted file mode 100644
index 3d024b62fe..0000000000
--- a/src/schema/metadata/DwellTime.yaml
+++ /dev/null
@@ -1,15 +0,0 @@
----
-name: DwellTime
-description: |
-  Actual dwell time (in seconds) of the receiver per point in the readout
-  direction, including any oversampling.
-  For Siemens, this corresponds to DICOM field 0019, 1018 (in ns).
-  This value is necessary for the optional readout distortion correction of
-  anatomicals in the HCP Pipelines.
-  It also usefully provides a handle on the readout bandwidth,
-  which isn't captured in the other metadata tags.
-  Not to be confused with `EffectiveEchoSpacing`, and the frequent mislabeling
-  of echo spacing (which is spacing in the phase encoding direction) as
-  "dwell time" (which is spacing in the readout direction).
-type: number
-unit: s
diff --git a/src/schema/metadata/ECGChannelCount.yaml b/src/schema/metadata/ECGChannelCount.yaml
deleted file mode 100644
index 2813a69e16..0000000000
--- a/src/schema/metadata/ECGChannelCount.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: ECGChannelCount
-description: |
-  Number of ECG channels.
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/ECOGChannelCount.yaml b/src/schema/metadata/ECOGChannelCount.yaml
deleted file mode 100644
index 859179ff0b..0000000000
--- a/src/schema/metadata/ECOGChannelCount.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: ECOGChannelCount
-description: |
-  Number of ECoG channels.
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/EEGChannelCount.yaml b/src/schema/metadata/EEGChannelCount.yaml
deleted file mode 100644
index 5dfca694d3..0000000000
--- a/src/schema/metadata/EEGChannelCount.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: EEGChannelCount
-description: |
-  Number of EEG channels recorded simultaneously (for example, `21`).
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/EEGCoordinateSystem.yaml b/src/schema/metadata/EEGCoordinateSystem.yaml
deleted file mode 100644
index 9e18cb910d..0000000000
--- a/src/schema/metadata/EEGCoordinateSystem.yaml
+++ /dev/null
@@ -1,15 +0,0 @@
----
-name: EEGCoordinateSystem
-description: |
-  Defines the coordinate system for the EEG sensors.
-
-  See
-  [Appendix VIII](/99-appendices/08-coordinate-systems.html)
-  for a list of restricted keywords for coordinate systems.
-  If `"Other"`, provide definition of the coordinate system in
-  `EEGCoordinateSystemDescription`.
-anyOf:
-  - $ref: _MEGCoordSys.yaml
-  - $ref: _EEGCoordSys.yaml
-  - $ref: _StandardTemplateCoordSys.yaml
-  - $ref: _StandardTemplateDeprecatedCoordSys.yaml
diff --git a/src/schema/metadata/EEGCoordinateSystemDescription.yaml b/src/schema/metadata/EEGCoordinateSystemDescription.yaml
deleted file mode 100644
index 452100c9ca..0000000000
--- a/src/schema/metadata/EEGCoordinateSystemDescription.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: EEGCoordinateSystemDescription
-description: |
-  Free-form text description of the coordinate system.
-  May also include a link to a documentation page or paper describing the
-  system in greater detail.
-type: string
diff --git a/src/schema/metadata/EEGCoordinateUnits.yaml b/src/schema/metadata/EEGCoordinateUnits.yaml
deleted file mode 100644
index 294e89ff94..0000000000
--- a/src/schema/metadata/EEGCoordinateUnits.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: EEGCoordinateUnits
-description: |
-  Units of the coordinates of `EEGCoordinateSystem`.
-  MUST be `"m"`, `"cm"`, or `"mm"`.
-type: string
-enum:
-  - m
-  - mm
-  - cm
-  - n/a
diff --git a/src/schema/metadata/EEGGround.yaml b/src/schema/metadata/EEGGround.yaml
deleted file mode 100644
index 5b83b1f6c5..0000000000
--- a/src/schema/metadata/EEGGround.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: EEGGround
-description: |
-  Description of the location of the ground electrode
-  (for example, `"placed on right mastoid (M2)"`).
-type: string
diff --git a/src/schema/metadata/EEGPlacementScheme.yaml b/src/schema/metadata/EEGPlacementScheme.yaml
deleted file mode 100644
index 9f07dfe273..0000000000
--- a/src/schema/metadata/EEGPlacementScheme.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: EEGPlacementScheme
-description: |
-  Placement scheme of EEG electrodes.
-  Either the name of a standardized placement system (for example, `"10-20"`)
-  or a list of standardized electrode names (for example, `["Cz", "Pz"]`).
-type: string
diff --git a/src/schema/metadata/EEGReference.yaml b/src/schema/metadata/EEGReference.yaml
deleted file mode 100644
index 558707ce24..0000000000
--- a/src/schema/metadata/EEGReference.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: EEGReference
-description: |
-  General description of the reference scheme used and (when applicable) of
-  location of the reference electrode in the raw recordings
-  (for example, `"left mastoid"`, `"Cz"`, `"CMS"`).
-  If different channels have a different reference,
-  this field should have a general description and the channel specific
-  reference should be defined in the `channels.tsv` file.
-type: string
diff --git a/src/schema/metadata/EMGChannelCount.yaml b/src/schema/metadata/EMGChannelCount.yaml
deleted file mode 100644
index ee94bb9852..0000000000
--- a/src/schema/metadata/EMGChannelCount.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: EMGChannelCount
-description: |
-  Number of EMG channels.
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/EOGChannelCount.yaml b/src/schema/metadata/EOGChannelCount.yaml
deleted file mode 100644
index ca3e631878..0000000000
--- a/src/schema/metadata/EOGChannelCount.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: EOGChannelCount
-description: |
-  Number of EOG channels.
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/EchoTime.yaml b/src/schema/metadata/EchoTime.yaml
deleted file mode 100644
index 564a95a981..0000000000
--- a/src/schema/metadata/EchoTime.yaml
+++ /dev/null
@@ -1,26 +0,0 @@
----
-name: EchoTime
-description: |
-  The echo time (TE) for the acquisition, specified in seconds.
-  Corresponds to DICOM Tag 0018, 0081 `Echo Time`
-  (please note that the DICOM term is in milliseconds not seconds).
-  The data type number may apply to files from any MRI modality concerned with
-  a single value for this field, or to the files in a
-  [file collection](/99-appendices/10-file-collections.html)
-  where the value of this field is iterated using the
-  [echo entity](/99-appendices/09-entities.html#echo).
-  The data type array provides a value for each volume in a 4D dataset and
-  should only be used when the volume timing is critical for interpretation
-  of the data, such as in
-  [ASL](/04-modality-specific-files/01-magnetic-resonance-imaging-data.html#\
-  arterial-spin-labeling-perfusion-data)
-  or variable echo time fMRI sequences.
-anyOf:
-  - type: number
-    unit: s
-    exclusiveMinimum: 0
-  - type: array
-    items:
-      type: number
-      unit: s
-      exclusiveMinimum: 0
diff --git a/src/schema/metadata/EchoTime1.yaml b/src/schema/metadata/EchoTime1.yaml
deleted file mode 100644
index 3ce454b2f5..0000000000
--- a/src/schema/metadata/EchoTime1.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: EchoTime1
-description: |
-  The time (in seconds) when the first (shorter) echo occurs.
-type: number
-unit: s
-exclusiveMinimum: 0
diff --git a/src/schema/metadata/EchoTime2.yaml b/src/schema/metadata/EchoTime2.yaml
deleted file mode 100644
index f3ec245204..0000000000
--- a/src/schema/metadata/EchoTime2.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: EchoTime2
-description: |
-  The time (in seconds) when the second (longer) echo occurs.
-type: number
-unit: s
-exclusiveMinimum: 0
diff --git a/src/schema/metadata/EchoTime_fmap.yaml b/src/schema/metadata/EchoTime_fmap.yaml
deleted file mode 100644
index 8f7d4bdd04..0000000000
--- a/src/schema/metadata/EchoTime_fmap.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-# This is a field map-specific definition for the EchoTime field.
-name: EchoTime
-description: |
-  The time (in seconds) when the echo corresponding to this map was acquired.
-type: number
-unit: s
-exclusiveMinimum: 0
diff --git a/src/schema/metadata/EffectiveEchoSpacing.yaml b/src/schema/metadata/EffectiveEchoSpacing.yaml
deleted file mode 100644
index 586bf762e3..0000000000
--- a/src/schema/metadata/EffectiveEchoSpacing.yaml
+++ /dev/null
@@ -1,16 +0,0 @@
----
-name: EffectiveEchoSpacing
-description: |
-  The "effective" sampling interval, specified in seconds,
-  between lines in the phase-encoding direction,
-  defined based on the size of the reconstructed image in the phase direction.
-  It is frequently, but incorrectly, referred to as "dwell time"
-  (see `DwellTime` parameter below for actual dwell time).
-  It is required for unwarping distortions using field maps.
-  Note that beyond just in-plane acceleration,
-  a variety of other manipulations to the phase encoding need to be accounted
-  for properly, including partial fourier, phase oversampling,
-  phase resolution, phase field-of-view and interpolation.
-type: number
-exclusiveMinimum: 0
-unit: s
diff --git a/src/schema/metadata/ElectricalStimulation.yaml b/src/schema/metadata/ElectricalStimulation.yaml
deleted file mode 100644
index c28a3834e9..0000000000
--- a/src/schema/metadata/ElectricalStimulation.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: ElectricalStimulation
-description: |
-  Boolean field to specify if electrical stimulation was done during the
-  recording (options are `true` or `false`). Parameters for event-like
-  stimulation should be specified in the events.tsv file.
-type: boolean
diff --git a/src/schema/metadata/ElectricalStimulationParameters.yaml b/src/schema/metadata/ElectricalStimulationParameters.yaml
deleted file mode 100644
index a46da4e9cd..0000000000
--- a/src/schema/metadata/ElectricalStimulationParameters.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: ElectricalStimulationParameters
-description: |
-  Free form description of stimulation parameters, such as frequency or shape.
-  Specific onsets can be specified in the events.tsv file.
-  Specific shapes can be described here in freeform text.
-type: string
diff --git a/src/schema/metadata/ElectrodeManufacturer.yaml b/src/schema/metadata/ElectrodeManufacturer.yaml
deleted file mode 100644
index dfea009e9e..0000000000
--- a/src/schema/metadata/ElectrodeManufacturer.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: ElectrodeManufacturer
-description: |
-  Can be used if all electrodes are of the same manufacturer
-  (for example, `"AD-TECH"`, `"DIXI"`).
-  If electrodes of different manufacturers are used,
-  please use the corresponding table in the `_electrodes.tsv` file.
-type: string
diff --git a/src/schema/metadata/ElectrodeManufacturersModelName.yaml b/src/schema/metadata/ElectrodeManufacturersModelName.yaml
deleted file mode 100644
index 19c45c51dc..0000000000
--- a/src/schema/metadata/ElectrodeManufacturersModelName.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: ElectrodeManufacturersModelName
-description: |
-  If different electrode types are used,
-  please use the corresponding table in the `_electrodes.tsv` file.
-type: string
diff --git a/src/schema/metadata/EpochLength.yaml b/src/schema/metadata/EpochLength.yaml
deleted file mode 100644
index a23f235941..0000000000
--- a/src/schema/metadata/EpochLength.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: EpochLength
-description: |
-  Duration of individual epochs in seconds (for example, `1`)
-  in case of epoched data.
-  If recording was continuous or discontinuous, leave out the field.
-type: number
-minimum: 0
diff --git a/src/schema/metadata/EstimationAlgorithm.yaml b/src/schema/metadata/EstimationAlgorithm.yaml
deleted file mode 100644
index 6465ed528b..0000000000
--- a/src/schema/metadata/EstimationAlgorithm.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: EstimationAlgorithm
-description: |
-  Type of algorithm used to perform fitting
-  (for example, linear, non-linear, LM and such).
-type: string
diff --git a/src/schema/metadata/EstimationReference.yaml b/src/schema/metadata/EstimationReference.yaml
deleted file mode 100644
index 2bb69499f8..0000000000
--- a/src/schema/metadata/EstimationReference.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: EstimationReference
-description: |
-  Reference to the study/studies on which the implementation is based.
-type: string
diff --git a/src/schema/metadata/EthicsApprovals.yaml b/src/schema/metadata/EthicsApprovals.yaml
deleted file mode 100644
index 4a201a6e64..0000000000
--- a/src/schema/metadata/EthicsApprovals.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: EthicsApprovals
-description: |
-  List of ethics committee approvals of the research protocols and/or
-  protocol identifiers.
-type: array
-items:
-  type: string
diff --git a/src/schema/metadata/FiducialsCoordinateSystem.yaml b/src/schema/metadata/FiducialsCoordinateSystem.yaml
deleted file mode 100644
index 8a34dcc3f1..0000000000
--- a/src/schema/metadata/FiducialsCoordinateSystem.yaml
+++ /dev/null
@@ -1,15 +0,0 @@
----
-name: FiducialsCoordinateSystem
-description: |
-  Defines the coordinate system for the fiducials.
-  Preferably the same as the `EEGCoordinateSystem`.
-  See
-  [Appendix VIII](/99-appendices/08-coordinate-systems.html)
-  for a list of restricted keywords for coordinate systems.
-  If `"Other"`, provide definition of the coordinate system in
-  `FiducialsCoordinateSystemDescription`.
-anyOf:
-  - $ref: _MEGCoordSys.yaml
-  - $ref: _EEGCoordSys.yaml
-  - $ref: _StandardTemplateCoordSys.yaml
-  - $ref: _StandardTemplateDeprecatedCoordSys.yaml
diff --git a/src/schema/metadata/FiducialsCoordinateSystemDescription.yaml b/src/schema/metadata/FiducialsCoordinateSystemDescription.yaml
deleted file mode 100644
index 4c7960df88..0000000000
--- a/src/schema/metadata/FiducialsCoordinateSystemDescription.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: FiducialsCoordinateSystemDescription
-description: |
-  Free-form text description of the coordinate system.
-  May also include a link to a documentation page or paper describing the
-  system in greater detail.
-type: string
diff --git a/src/schema/metadata/FiducialsCoordinateUnits.yaml b/src/schema/metadata/FiducialsCoordinateUnits.yaml
deleted file mode 100644
index 1138d0b40e..0000000000
--- a/src/schema/metadata/FiducialsCoordinateUnits.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: FiducialsCoordinateUnits
-description: |
-  Units in which the coordinates that are  listed in the field
-  `FiducialsCoordinateSystem` are represented.
-  MUST be `"m"`, `"cm"`, or `"mm"`.
-type: string
-enum:
-  - m
-  - mm
-  - cm
-  - n/a
diff --git a/src/schema/metadata/FiducialsCoordinates.yaml b/src/schema/metadata/FiducialsCoordinates.yaml
deleted file mode 100644
index 7ffc662d4d..0000000000
--- a/src/schema/metadata/FiducialsCoordinates.yaml
+++ /dev/null
@@ -1,16 +0,0 @@
----
-name: FiducialsCoordinates
-description: |
-  Key:value pairs of the labels and 3-D digitized position of anatomical
-  landmarks, interpreted following the `FiducialsCoordinateSystem`
-  (for example, `{"NAS": [12.7,21.3,13.9], "LPA": [5.2,11.3,9.6],
-  "RPA": [20.2,11.3,9.1]}`).
-  Each array MUST contain three numeric values corresponding to x, y, and z
-  axis of the coordinate system in that exact order.
-type: object
-additionalProperties:
-  type: array
-  items:
-    type: number
-  minItems: 3
-  maxItems: 3
diff --git a/src/schema/metadata/FiducialsDescription.yaml b/src/schema/metadata/FiducialsDescription.yaml
deleted file mode 100644
index c37866f3d8..0000000000
--- a/src/schema/metadata/FiducialsDescription.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: FiducialsDescription
-description: |
-  Free-form text description of how the fiducials such as vitamin-E capsules
-  were placed relative to anatomical landmarks,
-  and how the position of the fiducials were measured
-  (for example, both with Polhemus and with T1w MRI).
-type: string
diff --git a/src/schema/metadata/FlipAngle.yaml b/src/schema/metadata/FlipAngle.yaml
deleted file mode 100644
index 6352d3a065..0000000000
--- a/src/schema/metadata/FlipAngle.yaml
+++ /dev/null
@@ -1,29 +0,0 @@
----
-name: FlipAngle
-description: |
-  Flip angle (FA) for the acquisition, specified in degrees.
-  Corresponds to: DICOM Tag 0018, 1314 `Flip Angle`.
-  The data type number may apply to files from any MRI modality concerned with
-  a single value for this field, or to the files in a
-  [file collection](/99-appendices/10-file-collections.html)
-  where the value of this field is iterated using the
-  [flip entity](/99-appendices/09-entities.html#flip).
-  The data type array provides a value for each volume in a 4D dataset and
-  should only be used when the volume timing is critical for interpretation of
-  the data, such as in
-  [ASL](/04-modality-specific-files/01-magnetic-resonance-imaging-data.html#\
-  arterial-spin-labeling-perfusion-data)
-  or variable flip angle fMRI sequences.
-anyOf:
-  - type: number
-    unit: degree
-    exclusiveMinimum: 0
-    # The maximum should be checked
-    maximum: 360
-  - type: array
-    items:
-      type: number
-      unit: degree
-      exclusiveMinimum: 0
-      # The maximum should be checked
-      maximum: 360
diff --git a/src/schema/metadata/FrameDuration.yaml b/src/schema/metadata/FrameDuration.yaml
deleted file mode 100644
index 41d06bda02..0000000000
--- a/src/schema/metadata/FrameDuration.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: FrameDuration
-description: |
-  Time duration of each frame in default unit seconds.
-  This corresponds to DICOM Tag 0018, 1242 `Actual Frame Duration` converted
-  to seconds.
-type: array
-items:
-  type: number
-unit: s
diff --git a/src/schema/metadata/FrameTimesStart.yaml b/src/schema/metadata/FrameTimesStart.yaml
deleted file mode 100644
index a6471d745f..0000000000
--- a/src/schema/metadata/FrameTimesStart.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: FrameTimesStart
-description: |
-  Start times for all frames relative to `TimeZero` in default unit seconds.
-type: array
-items:
-  type: number
-unit: s
diff --git a/src/schema/metadata/Funding.yaml b/src/schema/metadata/Funding.yaml
deleted file mode 100644
index af3e597772..0000000000
--- a/src/schema/metadata/Funding.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Funding
-description: |
-  List of sources of funding (grant numbers).
-type: array
-items:
-  type: string
diff --git a/src/schema/metadata/GeneratedBy.yaml b/src/schema/metadata/GeneratedBy.yaml
deleted file mode 100644
index b615b740f9..0000000000
--- a/src/schema/metadata/GeneratedBy.yaml
+++ /dev/null
@@ -1,29 +0,0 @@
----
-name: GeneratedBy
-description: |
-  Used to specify provenance of the derived dataset.
-  See table below for contents of each object.
-type: array
-minItems: 1
-items:
-  type: object
-  properties:
-    Name:
-      type: string
-    Version:
-      type: string
-    Description:
-      type: string
-    CodeURL:
-      type: string
-      format: uri
-    Container:
-      type: object
-      properties:
-        Type:
-          type: string
-        Tag:
-          type: string
-        URI:
-          type: string
-          format: uri
diff --git a/src/schema/metadata/GeneticLevel.yaml b/src/schema/metadata/GeneticLevel.yaml
deleted file mode 100644
index 0404f98176..0000000000
--- a/src/schema/metadata/GeneticLevel.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: GeneticLevel
-description: |
-  Describes the level of analysis.
-  Values MUST be one of `"Genetic"`, `"Genomic"`, `"Epigenomic"`,
-  `"Transcriptomic"`, `"Metabolomic"`, or `"Proteomic"`.
-anyOf:
-  - $ref: _GeneticLevelEnum.yaml
-  - type: array
-    items:
-      $ref: _GeneticLevelEnum.yaml
diff --git a/src/schema/metadata/Genetics.Database.yaml b/src/schema/metadata/Genetics.Database.yaml
deleted file mode 100644
index 75ac9d29ad..0000000000
--- a/src/schema/metadata/Genetics.Database.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Genetics.Database
-description: |
-  [URI](/02-common-principles.html#uniform-resource-indicator)
-  of database where the dataset is hosted.
-type: string
-format: uri
diff --git a/src/schema/metadata/Genetics.Dataset.yaml b/src/schema/metadata/Genetics.Dataset.yaml
deleted file mode 100644
index 31e3a29470..0000000000
--- a/src/schema/metadata/Genetics.Dataset.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Genetics.Dataset
-description: |
-  [URI](/02-common-principles.html#uniform-resource-indicator)
-  where data can be retrieved.
-type: string
-format: uri
diff --git a/src/schema/metadata/Genetics.Descriptors.yaml b/src/schema/metadata/Genetics.Descriptors.yaml
deleted file mode 100644
index 7bfabde410..0000000000
--- a/src/schema/metadata/Genetics.Descriptors.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: Genetics.Descriptors
-description: |
-  List of relevant descriptors (for example, journal articles) for dataset
-  using a valid
-  [URI](/02-common-principles.html#uniform-resource-indicator)
-  when possible.
-anyOf:
-  - type: string
-  - type: array
-    items:
-      type: string
diff --git a/src/schema/metadata/Genetics.yaml b/src/schema/metadata/Genetics.yaml
deleted file mode 100644
index 1245772541..0000000000
--- a/src/schema/metadata/Genetics.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: Genetics
-description: |
-  An object containing information about the genetics descriptor.
-type: object
-properties:
-  Database:
-    $ref: Genetics.Database.yaml
-  Dataset:
-    $ref: Genetics.Dataset.yaml
-  Descriptors:
-    $ref: Genetics.Descriptors.yaml
diff --git a/src/schema/metadata/GradientSetType.yaml b/src/schema/metadata/GradientSetType.yaml
deleted file mode 100644
index 73722e8c35..0000000000
--- a/src/schema/metadata/GradientSetType.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: GradientSetType
-description: |
-  It should be possible to infer the gradient coil from the scanner model.
-  If not, for example because of a custom upgrade or use of a gradient
-  insert set, then the specifications of the actual gradient coil should be
-  reported independently.
-type: string
diff --git a/src/schema/metadata/HED.yaml b/src/schema/metadata/HED.yaml
deleted file mode 100644
index c9cee8494e..0000000000
--- a/src/schema/metadata/HED.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: HED
-description: |
-  Hierarchical Event Descriptor (HED) information,
-  see: [Appendix III](/99-appendices/03-hed.html) for details.
-anyOf:
-  - type: string
-  - type: object
-    additionalProperties:
-      type: string
diff --git a/src/schema/metadata/HEDVersion.yaml b/src/schema/metadata/HEDVersion.yaml
deleted file mode 100644
index 69c4fa8329..0000000000
--- a/src/schema/metadata/HEDVersion.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: HEDVersion
-description: |
-  If HED tags are used:
-  The version of the HED schema used to validate HED tags for study.
-type: string
diff --git a/src/schema/metadata/Haematocrit.yaml b/src/schema/metadata/Haematocrit.yaml
deleted file mode 100644
index c92059d598..0000000000
--- a/src/schema/metadata/Haematocrit.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Haematocrit
-description: |
-  Measured haematocrit, meaning the volume of erythrocytes divided by the
-  volume of whole blood.
-type: number
diff --git a/src/schema/metadata/HardcopyDeviceSoftwareVersion.yaml b/src/schema/metadata/HardcopyDeviceSoftwareVersion.yaml
deleted file mode 100644
index 106d5ebd3f..0000000000
--- a/src/schema/metadata/HardcopyDeviceSoftwareVersion.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: HardcopyDeviceSoftwareVersion
-description: |
-  Manufacturer's designation of the software of the device that created this
-  Hardcopy Image (the printer).
-  Corresponds to DICOM Tag 0018, 101A `Hardcopy Device Software Version`.
-type: string
diff --git a/src/schema/metadata/HardwareFilters.yaml b/src/schema/metadata/HardwareFilters.yaml
deleted file mode 100644
index 286968d1a9..0000000000
--- a/src/schema/metadata/HardwareFilters.yaml
+++ /dev/null
@@ -1,15 +0,0 @@
----
-name: HardwareFilters
-description: |
-  Object of temporal hardware filters applied, or "n/a" if the data is not
-  available. Each key:value pair in the JSON object is a name of the filter and
-  an object in which its parameters are defined as key:value pairs.
-  For example, `{"Highpass RC filter": {"Half amplitude cutoff (Hz)":
-  0.0159, "Roll-off": "6dB/Octave"}}`.
-anyOf:
-  - type: object
-    additionalProperties:
-      type: object
-  - type: string
-    enum:
-      - n/a
diff --git a/src/schema/metadata/HeadCircumference.yaml b/src/schema/metadata/HeadCircumference.yaml
deleted file mode 100644
index bea24728e3..0000000000
--- a/src/schema/metadata/HeadCircumference.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: HeadCircumference
-description: |
-  Circumference of the participant's head, expressed in cm (for example, `58`).
-type: number
-exclusiveMinimum: 0
-unit: cm
diff --git a/src/schema/metadata/HeadCoilCoordinateSystem.yaml b/src/schema/metadata/HeadCoilCoordinateSystem.yaml
deleted file mode 100644
index b517be9cb9..0000000000
--- a/src/schema/metadata/HeadCoilCoordinateSystem.yaml
+++ /dev/null
@@ -1,14 +0,0 @@
----
-name: HeadCoilCoordinateSystem
-description: |
-  Defines the coordinate system for the head coils.
-  See
-  [Appendix VIII](/99-appendices/08-coordinate-systems.html)
-  for a list of restricted keywords for coordinate systems.
-  If `"Other"`, provide definition of the coordinate system in
-  `HeadCoilCoordinateSystemDescription`.
-anyOf:
-  - $ref: _MEGCoordSys.yaml
-  - $ref: _EEGCoordSys.yaml
-  - $ref: _StandardTemplateCoordSys.yaml
-  - $ref: _StandardTemplateDeprecatedCoordSys.yaml
diff --git a/src/schema/metadata/HeadCoilCoordinateSystemDescription.yaml b/src/schema/metadata/HeadCoilCoordinateSystemDescription.yaml
deleted file mode 100644
index 51b7e2c907..0000000000
--- a/src/schema/metadata/HeadCoilCoordinateSystemDescription.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: HeadCoilCoordinateSystemDescription
-description:
-  Free-form text description of the coordinate system.
-  May also include a link to a documentation page or paper describing the
-  system in greater detail.
-type: string
diff --git a/src/schema/metadata/HeadCoilCoordinateUnits.yaml b/src/schema/metadata/HeadCoilCoordinateUnits.yaml
deleted file mode 100644
index 7c1cacd69a..0000000000
--- a/src/schema/metadata/HeadCoilCoordinateUnits.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: HeadCoilCoordinateUnits
-description: |
-  Units of the coordinates of `HeadCoilCoordinateSystem`.
-  MUST be `"m"`, `"cm"`, or `"mm"`.
-type: string
-enum:
-  - m
-  - mm
-  - cm
-  - n/a
diff --git a/src/schema/metadata/HeadCoilCoordinates.yaml b/src/schema/metadata/HeadCoilCoordinates.yaml
deleted file mode 100644
index 022434c677..0000000000
--- a/src/schema/metadata/HeadCoilCoordinates.yaml
+++ /dev/null
@@ -1,21 +0,0 @@
----
-name: HeadCoilCoordinates
-description: |
-  Key:value pairs describing head localization coil labels and their
-  coordinates, interpreted following the `HeadCoilCoordinateSystem`
-  (for example, `{"NAS": [12.7,21.3,13.9], "LPA": [5.2,11.3,9.6],
-  "RPA": [20.2,11.3,9.1]}`).
-  Note that coils are not always placed at locations that have a known
-  anatomical name (for example, for Elekta, Yokogawa systems); in that case
-  generic labels can be used
-  (for example, `{"coil1": [12.2,21.3,12.3], "coil2": [6.7,12.3,8.6],
-  "coil3": [21.9,11.0,8.1]}`).
-  Each array MUST contain three numeric values corresponding to x, y, and z
-  axis of the coordinate system in that exact order.
-type: object
-additionalProperties:
-  type: array
-  items:
-    type: number
-  minItems: 3
-  maxItems: 3
diff --git a/src/schema/metadata/HeadCoilFrequency.yaml b/src/schema/metadata/HeadCoilFrequency.yaml
deleted file mode 100644
index b26990e478..0000000000
--- a/src/schema/metadata/HeadCoilFrequency.yaml
+++ /dev/null
@@ -1,14 +0,0 @@
----
-name: HeadCoilFrequency
-description: |
-  List of frequencies (in Hz) used by the head localisation coils
-  ('HLC' in CTF systems, 'HPI' in Elekta, 'COH' in BTi/4D)
-  that track the subject's head position in the MEG helmet
-  (for example, `[293, 307, 314, 321]`).
-anyOf:
-  - type: number
-    unit: Hz
-  - type: array
-    items:
-      type: number
-      unit: Hz
diff --git a/src/schema/metadata/HowToAcknowledge.yaml b/src/schema/metadata/HowToAcknowledge.yaml
deleted file mode 100644
index 13c130d9db..0000000000
--- a/src/schema/metadata/HowToAcknowledge.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: HowToAcknowledge
-description: |
-  Text containing instructions on how researchers using this dataset should
-  acknowledge the original authors.
-  This field can also be used to define a publication that should be cited in
-  publications that use the dataset.
-type: string
diff --git a/src/schema/metadata/ImageDecayCorrected.yaml b/src/schema/metadata/ImageDecayCorrected.yaml
deleted file mode 100644
index 2f1f500a58..0000000000
--- a/src/schema/metadata/ImageDecayCorrected.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: ImageDecayCorrected
-description: |
-  Boolean flag specifying whether the image data have been decay-corrected.
-type: boolean
diff --git a/src/schema/metadata/ImageDecayCorrectionTime.yaml b/src/schema/metadata/ImageDecayCorrectionTime.yaml
deleted file mode 100644
index 1f030fa552..0000000000
--- a/src/schema/metadata/ImageDecayCorrectionTime.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: ImageDecayCorrectionTime
-description: |
-  Point in time from which the decay correction was applied with respect to
-  TimeZero in the default unit seconds.
-type: number
-unit: s
diff --git a/src/schema/metadata/InfusionRadioactivity.yaml b/src/schema/metadata/InfusionRadioactivity.yaml
deleted file mode 100644
index 969b57b83d..0000000000
--- a/src/schema/metadata/InfusionRadioactivity.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: InfusionRadioactivity
-description: |
-  Amount of radioactivity infused into the patient.
-  This value must be less than or equal to the total injected radioactivity
-  (`InjectedRadioactivity`).
-  Units should be the same as `InjectedRadioactivityUnits`.
-type: number
diff --git a/src/schema/metadata/InfusionSpeed.yaml b/src/schema/metadata/InfusionSpeed.yaml
deleted file mode 100644
index 511977c555..0000000000
--- a/src/schema/metadata/InfusionSpeed.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: InfusionSpeed
-description: |
-  If given, infusion speed.
-type: number
diff --git a/src/schema/metadata/InfusionSpeedUnits.yaml b/src/schema/metadata/InfusionSpeedUnits.yaml
deleted file mode 100644
index ad2880487a..0000000000
--- a/src/schema/metadata/InfusionSpeedUnits.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: InfusionSpeedUnits
-description: |
-  Unit of infusion speed (for example, `"mL/s"`).
-type: string
-format: unit
diff --git a/src/schema/metadata/InfusionStart.yaml b/src/schema/metadata/InfusionStart.yaml
deleted file mode 100644
index 472a9248a6..0000000000
--- a/src/schema/metadata/InfusionStart.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: InfusionStart
-description: |
-  Time of start of infusion with respect to `TimeZero` in the default unit
-  seconds.
-type: number
-unit: s
diff --git a/src/schema/metadata/InjectedMass.yaml b/src/schema/metadata/InjectedMass.yaml
deleted file mode 100644
index c1d6ef6597..0000000000
--- a/src/schema/metadata/InjectedMass.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
----
-name: InjectedMass
-description: |
-  Total mass of radiolabeled compound injected into subject (for example, 10).
-  This can be derived as the ratio of the `InjectedRadioactivity` and
-  `MolarRadioactivity`.
-  **For those tracers in which injected mass is not available (for example FDG)
-  can be set to `"n/a"`)**.
-anyOf:
-  - type: number
-  - type: string
-    enum:
-      - n/a
diff --git a/src/schema/metadata/InjectedMassPerWeight.yaml b/src/schema/metadata/InjectedMassPerWeight.yaml
deleted file mode 100644
index 0bbf6fa160..0000000000
--- a/src/schema/metadata/InjectedMassPerWeight.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: InjectedMassPerWeight
-description: |
-  Injected mass per kilogram bodyweight.
-type: number
diff --git a/src/schema/metadata/InjectedMassPerWeightUnits.yaml b/src/schema/metadata/InjectedMassPerWeightUnits.yaml
deleted file mode 100644
index 35c71627b6..0000000000
--- a/src/schema/metadata/InjectedMassPerWeightUnits.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: InjectedMassPerWeightUnits
-description: |
-  Unit format of the injected mass per kilogram bodyweight
-  (for example, `"ug/kg"`).
-type: string
-format: unit
diff --git a/src/schema/metadata/InjectedMassUnits.yaml b/src/schema/metadata/InjectedMassUnits.yaml
deleted file mode 100644
index 13989c59c3..0000000000
--- a/src/schema/metadata/InjectedMassUnits.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
----
-name: InjectedMassUnits
-description: |
-  Unit format of the mass of compound injected (for example, `"ug"` or
-  `"umol"`).
-  **Note this is not required for an FDG acquisition, since it is not available,
-  and SHOULD be set to `"n/a"`**.
-anyOf:
-  - type: string
-    format: unit
-  - type: string
-    enum:
-      - n/a
diff --git a/src/schema/metadata/InjectedRadioactivity.yaml b/src/schema/metadata/InjectedRadioactivity.yaml
deleted file mode 100644
index 44562dc29f..0000000000
--- a/src/schema/metadata/InjectedRadioactivity.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: InjectedRadioactivity
-description: |
-  Total amount of radioactivity injected into the patient (for example, 400).
-  For bolus-infusion experiments, this value should be the sum of all injected
-  radioactivity originating from both bolus and infusion.
-  Corresponds to DICOM Tag 0018, 1074 `Radionuclide Total Dose`.
-type: number
diff --git a/src/schema/metadata/InjectedRadioactivityUnits.yaml b/src/schema/metadata/InjectedRadioactivityUnits.yaml
deleted file mode 100644
index 1a3fa3bbb7..0000000000
--- a/src/schema/metadata/InjectedRadioactivityUnits.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: InjectedRadioactivityUnits
-description: |
-  Unit format of the specified injected radioactivity (for example, `"MBq"`).
-type: string
-format: unit
diff --git a/src/schema/metadata/InjectedVolume.yaml b/src/schema/metadata/InjectedVolume.yaml
deleted file mode 100644
index ce0c24c66b..0000000000
--- a/src/schema/metadata/InjectedVolume.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: InjectedVolume
-description: |
-  Injected volume of the radiotracer in the unit `"mL"`.
-type: number
-unit: mL
diff --git a/src/schema/metadata/InjectionEnd.yaml b/src/schema/metadata/InjectionEnd.yaml
deleted file mode 100644
index f80cde26b7..0000000000
--- a/src/schema/metadata/InjectionEnd.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: InjectionEnd
-description: |
-  Time of end of injection with respect to `TimeZero` in the default unit
-  seconds.
-type: number
-unit: s
diff --git a/src/schema/metadata/InjectionStart.yaml b/src/schema/metadata/InjectionStart.yaml
deleted file mode 100644
index 06dfab227c..0000000000
--- a/src/schema/metadata/InjectionStart.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: InjectionStart
-description: |
-  Time of start of injection with respect to `TimeZero` in the default unit
-  seconds.
-  This corresponds to DICOM Tag 0018, 1042 `Contrast/Bolus Start Time`
-  converted to seconds relative to `TimeZero`.
-type: number
-unit: s
diff --git a/src/schema/metadata/InstitutionAddress.yaml b/src/schema/metadata/InstitutionAddress.yaml
deleted file mode 100644
index 7df45943fc..0000000000
--- a/src/schema/metadata/InstitutionAddress.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: InstitutionAddress
-description: |
-  The address of the institution in charge of the equipment that produced the
-  measurements.
-type: string
diff --git a/src/schema/metadata/InstitutionName.yaml b/src/schema/metadata/InstitutionName.yaml
deleted file mode 100644
index 2fc3cb9435..0000000000
--- a/src/schema/metadata/InstitutionName.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: InstitutionName
-description: |
-  The name of the institution in charge of the equipment that produced the
-  measurements.
-type: string
diff --git a/src/schema/metadata/InstitutionalDepartmentName.yaml b/src/schema/metadata/InstitutionalDepartmentName.yaml
deleted file mode 100644
index 5534e9435e..0000000000
--- a/src/schema/metadata/InstitutionalDepartmentName.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: InstitutionalDepartmentName
-description: |
-  The department in the institution in charge of the equipment that produced
-  the measurements.
-type: string
diff --git a/src/schema/metadata/Instructions.yaml b/src/schema/metadata/Instructions.yaml
deleted file mode 100644
index 30dcf7b92e..0000000000
--- a/src/schema/metadata/Instructions.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Instructions
-description: |
-  Text of the instructions given to participants before the recording.
-type: string
diff --git a/src/schema/metadata/IntendedFor.yaml b/src/schema/metadata/IntendedFor.yaml
deleted file mode 100644
index 44b4c26bcb..0000000000
--- a/src/schema/metadata/IntendedFor.yaml
+++ /dev/null
@@ -1,15 +0,0 @@
----
-name: IntendedFor
-description: |
-  The paths to files for which the associated file is intended to be used.
-  Contains one or more filenames with paths relative to the participant
-  subfolder.
-  Paths need to use forward slashes instead of backward slashes,
-  regardless of operating system.
-anyOf:
-  - type: string
-    format: participant_relative
-  - type: array
-    items:
-      type: string
-      format: participant_relative
diff --git a/src/schema/metadata/InversionTime.yaml b/src/schema/metadata/InversionTime.yaml
deleted file mode 100644
index 1e5393481b..0000000000
--- a/src/schema/metadata/InversionTime.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: InversionTime
-description: |
-  The inversion time (TI) for the acquisition, specified in seconds.
-  Inversion time is the time after the middle of inverting RF pulse to middle
-  of excitation pulse to detect the amount of longitudinal magnetization.
-  Corresponds to DICOM Tag 0018, 0082 `Inversion Time`
-  (please note that the DICOM term is in milliseconds not seconds).
-type: number
-unit: s
-exclusiveMinimum: 0
diff --git a/src/schema/metadata/LabelingDistance.yaml b/src/schema/metadata/LabelingDistance.yaml
deleted file mode 100644
index b9e1cc0d10..0000000000
--- a/src/schema/metadata/LabelingDistance.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: LabelingDistance
-description: |
-  Distance from the center of the imaging slab to the center of the labeling
-  plane (`(P)CASL`) or the leading edge of the labeling slab (`PASL`),
-  in millimeters.
-  If the labeling is performed inferior to the isocenter,
-  this number should be negative.
-  Based on DICOM macro C.8.13.5.14.
-type: number
-unit: mm
diff --git a/src/schema/metadata/LabelingDuration.yaml b/src/schema/metadata/LabelingDuration.yaml
deleted file mode 100644
index 53e898e849..0000000000
--- a/src/schema/metadata/LabelingDuration.yaml
+++ /dev/null
@@ -1,24 +0,0 @@
----
-name: LabelingDuration
-description: |
-  Total duration of the labeling pulse train, in seconds,
-  corresponding to the temporal width of the labeling bolus for
-  `"PCASL"` or `"CASL"`.
-  In case all control-label volumes (or deltam or CBF) have the same
-  `LabelingDuration`, a scalar must be specified.
-  In case the control-label volumes (or deltam or cbf) have a different
-  `LabelingDuration`, an array of numbers must be specified,
-  for which any `m0scan` in the timeseries has a `LabelingDuration` of zero.
-  In case an array of numbers is provided,
-  its length should be equal to the number of volumes specified in
-  `*_aslcontext.tsv`.
-  Corresponds to DICOM Tag 0018, 9258 `ASL Pulse Train Duration`.
-anyOf:
-  - type: number
-    minimum: 0
-    unit: s
-  - type: array
-    items:
-      type: number
-      unit: s
-      minimum: 0
diff --git a/src/schema/metadata/LabelingEfficiency.yaml b/src/schema/metadata/LabelingEfficiency.yaml
deleted file mode 100644
index d6e7229497..0000000000
--- a/src/schema/metadata/LabelingEfficiency.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: LabelingEfficiency
-description: |
-  Labeling efficiency, specified as a number between zero and one,
-  only if obtained externally (for example phase-contrast based).
-type: number
-exclusiveMinimum: 0
diff --git a/src/schema/metadata/LabelingLocationDescription.yaml b/src/schema/metadata/LabelingLocationDescription.yaml
deleted file mode 100644
index d4cd014d69..0000000000
--- a/src/schema/metadata/LabelingLocationDescription.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: LabelingLocationDescription
-description: |
-  Description of the location of the labeling plane (`"CASL"` or `"PCASL"`) or
-  the labeling slab (`"PASL"`) that cannot be captured by fields
-  `LabelingOrientation` or `LabelingDistance`.
-  May include a link to an anonymized screenshot of the planning of the
-  labeling slab/plane with respect to the imaging slab or slices
-  `*_asllabeling.jpg`.
-  Based on DICOM macro C.8.13.5.14.
-type: string
diff --git a/src/schema/metadata/LabelingOrientation.yaml b/src/schema/metadata/LabelingOrientation.yaml
deleted file mode 100644
index 45c8b766b9..0000000000
--- a/src/schema/metadata/LabelingOrientation.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: LabelingOrientation
-description: |
-  Orientation of the labeling plane (`(P)CASL`) or slab (`PASL`).
-  The direction cosines of a normal vector perpendicular to the ASL labeling
-  slab or plane with respect to the patient.
-  Corresponds to DICOM Tag 0018, 9255 `ASL Slab Orientation`.
-type: array
-items:
-  type: number
diff --git a/src/schema/metadata/LabelingPulseAverageB1.yaml b/src/schema/metadata/LabelingPulseAverageB1.yaml
deleted file mode 100644
index 5d8991c291..0000000000
--- a/src/schema/metadata/LabelingPulseAverageB1.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: LabelingPulseAverageB1
-description: |
-  The average B1-field strength of the RF labeling pulses, in microteslas.
-  As an alternative, `LabelingPulseFlipAngle` can be provided.
-type: number
-exclusiveMinimum: 0
-unit: uT
diff --git a/src/schema/metadata/LabelingPulseAverageGradient.yaml b/src/schema/metadata/LabelingPulseAverageGradient.yaml
deleted file mode 100644
index c706587cc0..0000000000
--- a/src/schema/metadata/LabelingPulseAverageGradient.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: LabelingPulseAverageGradient
-description: |
-  The average labeling gradient, in milliteslas per meter.
-type: number
-exclusiveMinimum: 0
-unit: mT/m
diff --git a/src/schema/metadata/LabelingPulseDuration.yaml b/src/schema/metadata/LabelingPulseDuration.yaml
deleted file mode 100644
index e52491b364..0000000000
--- a/src/schema/metadata/LabelingPulseDuration.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: LabelingPulseDuration
-description: |
-  Duration of the individual labeling pulses, in milliseconds.
-type: number
-exclusiveMinimum: 0
-unit: ms
diff --git a/src/schema/metadata/LabelingPulseFlipAngle.yaml b/src/schema/metadata/LabelingPulseFlipAngle.yaml
deleted file mode 100644
index ced997fd5d..0000000000
--- a/src/schema/metadata/LabelingPulseFlipAngle.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: LabelingPulseFlipAngle
-description: |
-  The flip angle of a single labeling pulse, in degrees,
-  which can be given as an alternative to `LabelingPulseAverageB1`.
-type: number
-exclusiveMinimum: 0
-# The maximum should be checked
-maximum: 360
-unit: degree
diff --git a/src/schema/metadata/LabelingPulseInterval.yaml b/src/schema/metadata/LabelingPulseInterval.yaml
deleted file mode 100644
index 5fda2dbb10..0000000000
--- a/src/schema/metadata/LabelingPulseInterval.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: LabelingPulseInterval
-description: |
-  Delay between the peaks of the individual labeling pulses, in milliseconds.
-type: number
-exclusiveMinimum: 0
-unit: ms
diff --git a/src/schema/metadata/LabelingPulseMaximumGradient.yaml b/src/schema/metadata/LabelingPulseMaximumGradient.yaml
deleted file mode 100644
index ad6100cf37..0000000000
--- a/src/schema/metadata/LabelingPulseMaximumGradient.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: LabelingPulseMaximumGradient
-description: |
-  The maximum amplitude of the gradient switched on during the application of
-  the labeling RF pulse(s), in milliteslas per meter.
-type: number
-exclusiveMinimum: 0
-unit: mT/m
diff --git a/src/schema/metadata/LabelingSlabThickness.yaml b/src/schema/metadata/LabelingSlabThickness.yaml
deleted file mode 100644
index 5d4d56bc9f..0000000000
--- a/src/schema/metadata/LabelingSlabThickness.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: LabelingSlabThickness
-description: |
-  Thickness of the labeling slab in millimeters.
-  For non-selective FAIR a zero is entered.
-  Corresponds to DICOM Tag 0018, 9254 `ASL Slab Thickness`.
-type: number
-exclusiveMinimum: 0
-unit: mm
diff --git a/src/schema/metadata/Levels.yaml b/src/schema/metadata/Levels.yaml
deleted file mode 100644
index 93c52ec71e..0000000000
--- a/src/schema/metadata/Levels.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: Levels
-description: |
-  For categorical variables: An object of possible values (keys) and their
-  descriptions (values).
-type: object
-additionalProperties:
-  type: string
diff --git a/src/schema/metadata/License.yaml b/src/schema/metadata/License.yaml
deleted file mode 100644
index 80e25d996f..0000000000
--- a/src/schema/metadata/License.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: License
-description: |
-  The license for the dataset.
-  The use of license name abbreviations is RECOMMENDED for specifying a license
-  (see [Appendix II](/99-appendices/02-licenses.html)).
-  The corresponding full license text MAY be specified in an additional
-  `LICENSE` file.
-type: string
diff --git a/src/schema/metadata/LongName.yaml b/src/schema/metadata/LongName.yaml
deleted file mode 100644
index 549812546e..0000000000
--- a/src/schema/metadata/LongName.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: LongName
-description: |
-  Long (unabbreviated) name of the column.
-type: string
diff --git a/src/schema/metadata/LookLocker.yaml b/src/schema/metadata/LookLocker.yaml
deleted file mode 100644
index 744265fcf8..0000000000
--- a/src/schema/metadata/LookLocker.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: LookLocker
-description: |
-  Boolean indicating if a Look-Locker readout is used.
-type: boolean
diff --git a/src/schema/metadata/M0Estimate.yaml b/src/schema/metadata/M0Estimate.yaml
deleted file mode 100644
index 10e343a6c1..0000000000
--- a/src/schema/metadata/M0Estimate.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: M0Estimate
-description: |
-  A single numerical whole-brain M0 value (referring to the M0 of blood),
-  only if obtained externally
-  (for example retrieved from CSF in a separate measurement).
-type: number
-exclusiveMinimum: 0
diff --git a/src/schema/metadata/M0Type.yaml b/src/schema/metadata/M0Type.yaml
deleted file mode 100644
index 69493a7174..0000000000
--- a/src/schema/metadata/M0Type.yaml
+++ /dev/null
@@ -1,15 +0,0 @@
----
-name: M0Type
-description: |
-  Describes the presence of M0 information, as either:
-  `"Separate"` when a separate `*_m0scan.nii[.gz]` is present,
-  `"Included"` when an m0scan volume is contained within the current
-  `*_asl.nii[.gz]`,
-  `"Estimate"` when a single whole-brain M0 value is provided, or
-  `"Absent"` when no specific M0 information is present.
-type: string
-enum:
-  - Separate
-  - Included
-  - Estimate
-  - Absent
diff --git a/src/schema/metadata/MEGChannelCount.yaml b/src/schema/metadata/MEGChannelCount.yaml
deleted file mode 100644
index f64b7352f5..0000000000
--- a/src/schema/metadata/MEGChannelCount.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MEGChannelCount
-description: |
-  Number of MEG channels (for example, 275).
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/MEGCoordinateSystem.yaml b/src/schema/metadata/MEGCoordinateSystem.yaml
deleted file mode 100644
index 320da2ac4b..0000000000
--- a/src/schema/metadata/MEGCoordinateSystem.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
----
-name: MEGCoordinateSystem
-description: |
-  Defines the coordinate system for the MEG sensors.
-  See [Appendix VIII](/99-appendices/08-coordinate-systems.html)
-  for a list of restricted keywords for coordinate systems.
-  If `"Other"`, provide definition of the coordinate system in
-  `MEGCoordinateSystemDescription`.
-anyOf:
-  - $ref: _MEGCoordSys.yaml
-  - $ref: _EEGCoordSys.yaml
-  - $ref: _StandardTemplateCoordSys.yaml
-  - $ref: _StandardTemplateDeprecatedCoordSys.yaml
diff --git a/src/schema/metadata/MEGCoordinateSystemDescription.yaml b/src/schema/metadata/MEGCoordinateSystemDescription.yaml
deleted file mode 100644
index ec7d571455..0000000000
--- a/src/schema/metadata/MEGCoordinateSystemDescription.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: MEGCoordinateSystemDescription
-description: |
-  Free-form text description of the coordinate system.
-  May also include a link to a documentation page or paper describing the
-  system in greater detail.
-type: string
diff --git a/src/schema/metadata/MEGCoordinateUnits.yaml b/src/schema/metadata/MEGCoordinateUnits.yaml
deleted file mode 100644
index 062f71b09b..0000000000
--- a/src/schema/metadata/MEGCoordinateUnits.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: MEGCoordinateUnits
-description: |
-  Units of the coordinates of `MEGCoordinateSystem`.
-  MUST be `"m"`, `"cm"`, or `"mm"`.
-type: string
-enum:
-  - m
-  - mm
-  - cm
-  - n/a
diff --git a/src/schema/metadata/MEGREFChannelCount.yaml b/src/schema/metadata/MEGREFChannelCount.yaml
deleted file mode 100644
index 6a735483de..0000000000
--- a/src/schema/metadata/MEGREFChannelCount.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: MEGREFChannelCount
-description: |
-  Number of MEG reference channels (for example, 23).
-  For systems without such channels (for example, Neuromag Vectorview),
-  `MEGREFChannelCount` should be set to `0`.
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/MRAcquisitionType.yaml b/src/schema/metadata/MRAcquisitionType.yaml
deleted file mode 100644
index 7fad51a603..0000000000
--- a/src/schema/metadata/MRAcquisitionType.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: MRAcquisitionType
-description: |
-  Possible values: `"2D"` or `"3D"`.
-  Type of sequence readout.
-  Corresponds to DICOM Tag 0018, 0023 `MR Acquisition Type`.
-type: string
-enum:
-  - 2D
-  - 3D
diff --git a/src/schema/metadata/MRTransmitCoilSequence.yaml b/src/schema/metadata/MRTransmitCoilSequence.yaml
deleted file mode 100644
index 3b77497c5f..0000000000
--- a/src/schema/metadata/MRTransmitCoilSequence.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MRTransmitCoilSequence
-description: |
-  This is a relevant field if a non-standard transmit coil is used.
-  Corresponds to DICOM Tag 0018, 9049 `MR Transmit Coil Sequence`.
-type: string
diff --git a/src/schema/metadata/MTNumberOfPulses.yaml b/src/schema/metadata/MTNumberOfPulses.yaml
deleted file mode 100644
index 2a5e0fb49a..0000000000
--- a/src/schema/metadata/MTNumberOfPulses.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: MTNumberOfPulses
-description: |
-  The number of magnetization transfer RF pulses applied before the readout.
-type: number
diff --git a/src/schema/metadata/MTOffsetFrequency.yaml b/src/schema/metadata/MTOffsetFrequency.yaml
deleted file mode 100644
index 33989f7dab..0000000000
--- a/src/schema/metadata/MTOffsetFrequency.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: MTOffsetFrequency
-description: |
-  The frequency offset of the magnetization transfer pulse with respect to the
-  central H1 Larmor frequency in Hertz (Hz).
-type: number
-unit: Hz
diff --git a/src/schema/metadata/MTPulseBandwidth.yaml b/src/schema/metadata/MTPulseBandwidth.yaml
deleted file mode 100644
index 5dd5ee62e8..0000000000
--- a/src/schema/metadata/MTPulseBandwidth.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MTPulseBandwidth
-description: |
-  The excitation bandwidth of the magnetization transfer pulse in Hertz (Hz).
-type: number
-unit: Hz
diff --git a/src/schema/metadata/MTPulseDuration.yaml b/src/schema/metadata/MTPulseDuration.yaml
deleted file mode 100644
index e70285c4b1..0000000000
--- a/src/schema/metadata/MTPulseDuration.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MTPulseDuration
-description: |
-  Duration of the magnetization transfer RF pulse in seconds.
-type: number
-unit: s
diff --git a/src/schema/metadata/MTPulseShape.yaml b/src/schema/metadata/MTPulseShape.yaml
deleted file mode 100644
index 8bbf0d8420..0000000000
--- a/src/schema/metadata/MTPulseShape.yaml
+++ /dev/null
@@ -1,17 +0,0 @@
----
-name: MTPulseShape
-description: |
-  Shape of the magnetization transfer RF pulse waveform.
-  Accepted values: `"HARD"`, `"GAUSSIAN"`,
-  `"GAUSSHANN"` (gaussian pulse with Hanning window),
-  `"SINC"`, `"SINCHANN"` (sinc pulse with Hanning window),
-  `"SINCGAUSS"` (sinc pulse with Gaussian window), `"FERMI"`.
-type: string
-enum:
-  - HARD
-  - GAUSSIAN
-  - GAUSSHANN
-  - SINC
-  - SINCHANN
-  - SINCGAUSS
-  - FERMI
diff --git a/src/schema/metadata/MTState.yaml b/src/schema/metadata/MTState.yaml
deleted file mode 100644
index bccf710ec9..0000000000
--- a/src/schema/metadata/MTState.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MTState
-description: |
-  Boolean stating whether the magnetization transfer pulse is applied.
-  Corresponds to DICOM Tag 0018, 9020 `Magnetization Transfer`.
-type: boolean
diff --git a/src/schema/metadata/MagneticFieldStrength.yaml b/src/schema/metadata/MagneticFieldStrength.yaml
deleted file mode 100644
index 0a8d44bfd4..0000000000
--- a/src/schema/metadata/MagneticFieldStrength.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MagneticFieldStrength
-description: |
-  Nominal field strength of MR magnet in Tesla.
-  Corresponds to DICOM Tag 0018, 0087 `Magnetic Field Strength`.
-type: number
diff --git a/src/schema/metadata/Manual.yaml b/src/schema/metadata/Manual.yaml
deleted file mode 100644
index 5f6423d100..0000000000
--- a/src/schema/metadata/Manual.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Manual
-description: |
-  Indicates if the segmentation was performed manually or via an automated
-  process.
-type: boolean
diff --git a/src/schema/metadata/Manufacturer.yaml b/src/schema/metadata/Manufacturer.yaml
deleted file mode 100644
index c2745d6873..0000000000
--- a/src/schema/metadata/Manufacturer.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Manufacturer
-description: |
-  Manufacturer of the equipment that produced the measurements.
-type: string
diff --git a/src/schema/metadata/ManufacturersModelName.yaml b/src/schema/metadata/ManufacturersModelName.yaml
deleted file mode 100644
index ee2bfed855..0000000000
--- a/src/schema/metadata/ManufacturersModelName.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: ManufacturersModelName
-description: |
-  Manufacturer's model name of the equipment that produced the measurements.
-type: string
diff --git a/src/schema/metadata/MatrixCoilMode.yaml b/src/schema/metadata/MatrixCoilMode.yaml
deleted file mode 100644
index bd64a37e01..0000000000
--- a/src/schema/metadata/MatrixCoilMode.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: MatrixCoilMode
-description: |
-  (If used)
-  A method for reducing the number of independent channels by combining in
-  analog the signals from multiple coil elements.
-  There are typically different default modes when using un-accelerated or
-  accelerated (for example, `"GRAPPA"`, `"SENSE"`) imaging.
-type: string
diff --git a/src/schema/metadata/MaxMovement.yaml b/src/schema/metadata/MaxMovement.yaml
deleted file mode 100644
index 24545a563c..0000000000
--- a/src/schema/metadata/MaxMovement.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: MaxMovement
-description: |
-  Maximum head movement (in mm) detected during the recording,
-  as measured by the head localisation coils (for example, 4.8).
-type: number
-unit: mm
diff --git a/src/schema/metadata/MetaboliteAvail.yaml b/src/schema/metadata/MetaboliteAvail.yaml
deleted file mode 100644
index 74b03f0612..0000000000
--- a/src/schema/metadata/MetaboliteAvail.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: MetaboliteAvail
-description: |
-  Boolean that specifies if metabolite measurements are available.
-  If `true`, the `metabolite_parent_fraction` column MUST be present in the
-  corresponding `*_blood.tsv` file.
-type: boolean
diff --git a/src/schema/metadata/MetaboliteMethod.yaml b/src/schema/metadata/MetaboliteMethod.yaml
deleted file mode 100644
index 078b40d8db..0000000000
--- a/src/schema/metadata/MetaboliteMethod.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: MetaboliteMethod
-description: |
-  Method used to measure metabolites.
-type: string
diff --git a/src/schema/metadata/MetaboliteRecoveryCorrectionApplied.yaml b/src/schema/metadata/MetaboliteRecoveryCorrectionApplied.yaml
deleted file mode 100644
index 36a20b139c..0000000000
--- a/src/schema/metadata/MetaboliteRecoveryCorrectionApplied.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: MetaboliteRecoveryCorrectionApplied
-description: |
-  Metabolite recovery correction from the HPLC, for tracers where it changes
-  with time postinjection.
-  If `true`, the `hplc_recovery_fractions` column MUST be present in the
-  corresponding `*_blood.tsv` file.
-type: boolean
diff --git a/src/schema/metadata/MiscChannelCount.yaml b/src/schema/metadata/MiscChannelCount.yaml
deleted file mode 100644
index 60dcfb4853..0000000000
--- a/src/schema/metadata/MiscChannelCount.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MiscChannelCount
-description: |
-  Number of miscellaneous analog channels for auxiliary signals.
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/MixingTime.yaml b/src/schema/metadata/MixingTime.yaml
deleted file mode 100644
index c81b50b903..0000000000
--- a/src/schema/metadata/MixingTime.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: MixingTime
-description: |
-  In the context of a stimulated- and spin-echo 3D EPI sequence for B1+ mapping,
-  corresponds to the interval between spin- and stimulated-echo pulses.
-  In the context of a diffusion-weighted double spin-echo sequence,
-  corresponds to the interval between two successive diffusion sensitizing
-  gradients, specified in seconds.
-type: number
-unit: s
diff --git a/src/schema/metadata/ModeOfAdministration.yaml b/src/schema/metadata/ModeOfAdministration.yaml
deleted file mode 100644
index 2de8bcaa4a..0000000000
--- a/src/schema/metadata/ModeOfAdministration.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: ModeOfAdministration
-description: |
-  Mode of administration of the injection
-  (for example, `"bolus"`, `"infusion"`, or `"bolus-infusion"`).
-type: string
diff --git a/src/schema/metadata/MolarActivity.yaml b/src/schema/metadata/MolarActivity.yaml
deleted file mode 100644
index 3a3a541a7d..0000000000
--- a/src/schema/metadata/MolarActivity.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MolarActivity
-description: |
-  Molar activity of compound injected.
-  Corresponds to DICOM Tag 0018, 1077 `Radiopharmaceutical Specific Activity`.
-type: number
diff --git a/src/schema/metadata/MolarActivityMeasTime.yaml b/src/schema/metadata/MolarActivityMeasTime.yaml
deleted file mode 100644
index e591e20c6f..0000000000
--- a/src/schema/metadata/MolarActivityMeasTime.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: MolarActivityMeasTime
-description: |
-  Time to which molar radioactivity measurement above applies in the default
-  unit `"hh:mm:ss"`.
-type: string
-pattern: ^(?:2[0-3]|[01][0-9]):[0-5][0-9]:[0-5][0-9]$
diff --git a/src/schema/metadata/MolarActivityUnits.yaml b/src/schema/metadata/MolarActivityUnits.yaml
deleted file mode 100644
index 763b5b3663..0000000000
--- a/src/schema/metadata/MolarActivityUnits.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MolarActivityUnits
-description: |
-  Unit of the specified molar radioactivity (for example, `"GBq/umol"`).
-type: string
-format: unit
diff --git a/src/schema/metadata/MultibandAccelerationFactor.yaml b/src/schema/metadata/MultibandAccelerationFactor.yaml
deleted file mode 100644
index 23db38a370..0000000000
--- a/src/schema/metadata/MultibandAccelerationFactor.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MultibandAccelerationFactor
-description: |
-  The multiband factor, for multiband acquisitions.
-# TODO: Determine if integer would be more appropriate.
-type: number
diff --git a/src/schema/metadata/MultipartID.yaml b/src/schema/metadata/MultipartID.yaml
deleted file mode 100644
index cf8c507815..0000000000
--- a/src/schema/metadata/MultipartID.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: MultipartID
-description: |
-  A unique (per participant) label tagging DWI runs that are part of a
-  multipart scan.
-type: string
diff --git a/src/schema/metadata/Name.yaml b/src/schema/metadata/Name.yaml
deleted file mode 100644
index 94f9eabfc1..0000000000
--- a/src/schema/metadata/Name.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Name
-description: |
-  Name of the dataset.
-type: string
diff --git a/src/schema/metadata/NegativeContrast.yaml b/src/schema/metadata/NegativeContrast.yaml
deleted file mode 100644
index 3b11aff793..0000000000
--- a/src/schema/metadata/NegativeContrast.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: NegativeContrast
-description: |
-  `true` or `false` value specifying whether increasing voxel intensity
-  (within sample voxels) denotes a decreased value with respect to the
-  contrast suffix.
-  This is commonly the case when Cerebral Blood Volume is estimated via
-  usage of a contrast agent in conjunction with a T2\* weighted acquisition
-  protocol.
-type: boolean
diff --git a/src/schema/metadata/NonlinearGradientCorrection.yaml b/src/schema/metadata/NonlinearGradientCorrection.yaml
deleted file mode 100644
index 378599bf2b..0000000000
--- a/src/schema/metadata/NonlinearGradientCorrection.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: NonlinearGradientCorrection
-description: |
-  Boolean stating if the image saved has been corrected for gradient
-  nonlinearities by the scanner sequence.
-type: boolean
diff --git a/src/schema/metadata/NumberOfVolumesDiscardedByScanner.yaml b/src/schema/metadata/NumberOfVolumesDiscardedByScanner.yaml
deleted file mode 100644
index 1b4cb51484..0000000000
--- a/src/schema/metadata/NumberOfVolumesDiscardedByScanner.yaml
+++ /dev/null
@@ -1,15 +0,0 @@
----
-name: NumberOfVolumesDiscardedByScanner
-description: |
-  Number of volumes ("dummy scans") discarded by the scanner
-  (as opposed to those discarded by the user post hoc)
-  before saving the imaging file.
-  For example, a sequence that automatically discards the first 4 volumes
-  before saving would have this field as 4.
-  A sequence that doesn't discard dummy scans would have this set to 0.
-  Please note that the onsets recorded in the `events.tsv` file should always
-  refer to the beginning of the acquisition of the first volume in the
-  corresponding imaging file - independent of the value of
-  `NumberOfVolumesDiscardedByScanner` field.
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/NumberOfVolumesDiscardedByUser.yaml b/src/schema/metadata/NumberOfVolumesDiscardedByUser.yaml
deleted file mode 100644
index a474549afb..0000000000
--- a/src/schema/metadata/NumberOfVolumesDiscardedByUser.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: NumberOfVolumesDiscardedByUser
-description: |
-  Number of volumes ("dummy scans") discarded by the user before including the
-  file in the dataset.
-  If possible, including all of the volumes is strongly recommended.
-  Please note that the onsets recorded in the `events.tsv` file should always
-  refer to the beginning of the acquisition of the first volume in the
-  corresponding imaging file - independent of the value of
-  `NumberOfVolumesDiscardedByUser` field.
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/NumberShots.yaml b/src/schema/metadata/NumberShots.yaml
deleted file mode 100644
index bea6e54a12..0000000000
--- a/src/schema/metadata/NumberShots.yaml
+++ /dev/null
@@ -1,18 +0,0 @@
----
-name: NumberShots
-description: |
-  The number of RF excitations needed to reconstruct a slice or volume
-  (may be referred to as partition).
-  Please mind that this is not the same as Echo Train Length which denotes the
-  number of k-space lines collected after excitation in a multi-echo readout.
-  The data type array is applicable for specifying this parameter before and
-  after the k-space center is sampled.
-  Please see
-  [`NumberShots` metadata field]\
-  (/99-appendices/11-qmri.html#numbershots-metadata-field)
-  in the qMRI appendix for corresponding calculations.
-anyOf:
-  - type: number
-  - type: array
-    items:
-      type: number
diff --git a/src/schema/metadata/OperatingSystem.yaml b/src/schema/metadata/OperatingSystem.yaml
deleted file mode 100644
index 430020c07a..0000000000
--- a/src/schema/metadata/OperatingSystem.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: OperatingSystem
-description: |
-  Operating system used to run the stimuli presentation software
-  (for formatting recommendations, see examples below this table).
-type: string
diff --git a/src/schema/metadata/PASLType.yaml b/src/schema/metadata/PASLType.yaml
deleted file mode 100644
index 7c1b54149c..0000000000
--- a/src/schema/metadata/PASLType.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: PASLType
-description: |
-  Type of the labeling pulse of the `PASL` labeling,
-  for example `"FAIR"`, `"EPISTAR"`, or `"PICORE"`.
-type: string
diff --git a/src/schema/metadata/PCASLType.yaml b/src/schema/metadata/PCASLType.yaml
deleted file mode 100644
index 38c36198c1..0000000000
--- a/src/schema/metadata/PCASLType.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: PCASLType
-description: |
-  Type the gradient pulses used in the `"control"` condition:
-  `"balanced"` or `"unbalanced"`.
-type: string
-enum:
-  - balanced
-  - unbalanced
diff --git a/src/schema/metadata/ParallelAcquisitionTechnique.yaml b/src/schema/metadata/ParallelAcquisitionTechnique.yaml
deleted file mode 100644
index 235a62756f..0000000000
--- a/src/schema/metadata/ParallelAcquisitionTechnique.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: ParallelAcquisitionTechnique
-description: |
-  The type of parallel imaging used (for example `"GRAPPA"`, `"SENSE"`).
-  Corresponds to DICOM Tag 0018, 9078 `Parallel Acquisition Technique`.
-type: string
diff --git a/src/schema/metadata/ParallelReductionFactorInPlane.yaml b/src/schema/metadata/ParallelReductionFactorInPlane.yaml
deleted file mode 100644
index 64d882b383..0000000000
--- a/src/schema/metadata/ParallelReductionFactorInPlane.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: ParallelReductionFactorInPlane
-description: |
-  The parallel imaging (for instance, GRAPPA) factor.
-  Use the denominator of the fraction of k-space encoded for each slice.
-  For example, 2 means half of k-space is encoded.
-  Corresponds to DICOM Tag 0018, 9069 `Parallel Reduction Factor In-plane`.
-type: number
diff --git a/src/schema/metadata/PartialFourier.yaml b/src/schema/metadata/PartialFourier.yaml
deleted file mode 100644
index 73ee0a8655..0000000000
--- a/src/schema/metadata/PartialFourier.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: PartialFourier
-description: |
-  The fraction of partial Fourier information collected.
-  Corresponds to DICOM Tag 0018, 9081 `Partial Fourier`.
-type: number
diff --git a/src/schema/metadata/PartialFourierDirection.yaml b/src/schema/metadata/PartialFourierDirection.yaml
deleted file mode 100644
index 0cd5dc8d50..0000000000
--- a/src/schema/metadata/PartialFourierDirection.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: PartialFourierDirection
-description: |
-  The direction where only partial Fourier information was collected.
-  Corresponds to DICOM Tag 0018, 9036 `Partial Fourier Direction`.
-type: string
diff --git a/src/schema/metadata/PharmaceuticalDoseAmount.yaml b/src/schema/metadata/PharmaceuticalDoseAmount.yaml
deleted file mode 100644
index a31952fc34..0000000000
--- a/src/schema/metadata/PharmaceuticalDoseAmount.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: PharmaceuticalDoseAmount
-description: |
-  Dose amount of pharmaceutical coadministered with tracer.
-anyOf:
-  - type: number
-  - type: array
-    items:
-      type: number
diff --git a/src/schema/metadata/PharmaceuticalDoseRegimen.yaml b/src/schema/metadata/PharmaceuticalDoseRegimen.yaml
deleted file mode 100644
index a826ef5057..0000000000
--- a/src/schema/metadata/PharmaceuticalDoseRegimen.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: PharmaceuticalDoseRegimen
-description: |
-  Details of the pharmaceutical dose regimen.
-  Either adequate description or short-code relating to regimen documented
-  elsewhere (for example, `"single oral bolus"`).
-type: string
diff --git a/src/schema/metadata/PharmaceuticalDoseTime.yaml b/src/schema/metadata/PharmaceuticalDoseTime.yaml
deleted file mode 100644
index bb5c9ce02b..0000000000
--- a/src/schema/metadata/PharmaceuticalDoseTime.yaml
+++ /dev/null
@@ -1,16 +0,0 @@
----
-name: PharmaceuticalDoseTime
-description: |
-  Time of administration of pharmaceutical dose, relative to time zero.
-  For an infusion, this should be a vector with two elements specifying the
-  start and end of the infusion period. For more complex dose regimens,
-  the regimen description should be complete enough to enable unambiguous
-  interpretation of `PharmaceuticalDoseTime`.
-  Unit format of the specified pharmaceutical dose time MUST be seconds.
-anyOf:
-  - type: number
-    unit: s
-  - type: array
-    items:
-      type: number
-      unit: s
diff --git a/src/schema/metadata/PharmaceuticalDoseUnits.yaml b/src/schema/metadata/PharmaceuticalDoseUnits.yaml
deleted file mode 100644
index d3fa04a04a..0000000000
--- a/src/schema/metadata/PharmaceuticalDoseUnits.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: PharmaceuticalDoseUnits
-description: |
-  Unit format relating to pharmaceutical dose
-  (for example, `"mg"` or `"mg/kg"`).
-type: string
-format: unit
diff --git a/src/schema/metadata/PharmaceuticalName.yaml b/src/schema/metadata/PharmaceuticalName.yaml
deleted file mode 100644
index b80aafee6f..0000000000
--- a/src/schema/metadata/PharmaceuticalName.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: PharmaceuticalName
-description: |
-  Name of pharmaceutical coadministered with tracer.
-type: string
diff --git a/src/schema/metadata/PhaseEncodingDirection.yaml b/src/schema/metadata/PhaseEncodingDirection.yaml
deleted file mode 100644
index 96109ce9a3..0000000000
--- a/src/schema/metadata/PhaseEncodingDirection.yaml
+++ /dev/null
@@ -1,22 +0,0 @@
----
-name: PhaseEncodingDirection
-description: |
-  Possible values: `"i"`, `"j"`, `"k"`, `"i-"`, `"j-"`, `"k-"`.
-  The letters `i`, `j`, `k` correspond to the first, second and third axis of
-  the data in the NIFTI file.
-  The polarity of the phase encoding is assumed to go from zero index to
-  maximum index unless `-` sign is present
-  (then the order is reversed - starting from the highest index instead of
-  zero).
-  `PhaseEncodingDirection` is defined as the direction along which phase is was
-  modulated which may result in visible distortions.
-  Note that this is not the same as the DICOM term
-  `InPlanePhaseEncodingDirection` which can have `ROW` or `COL` values.
-type: string
-enum:
-  - i
-  - j
-  - k
-  - i-
-  - j-
-  - k-
diff --git a/src/schema/metadata/PlasmaAvail.yaml b/src/schema/metadata/PlasmaAvail.yaml
deleted file mode 100644
index c7358dc1c6..0000000000
--- a/src/schema/metadata/PlasmaAvail.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: PlasmaAvail
-description: |
-  Boolean that specifies if plasma measurements are available.
-type: boolean
diff --git a/src/schema/metadata/PlasmaFreeFraction.yaml b/src/schema/metadata/PlasmaFreeFraction.yaml
deleted file mode 100644
index b96fbdf8fb..0000000000
--- a/src/schema/metadata/PlasmaFreeFraction.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: PlasmaFreeFraction
-description: |
-  Measured free fraction in plasma, meaning the concentration of free compound
-  in plasma divided by total concentration of compound in plasma
-  (Units: 0-100%).
-type: number
-minimum: 0
-maximum: 100
diff --git a/src/schema/metadata/PlasmaFreeFractionMethod.yaml b/src/schema/metadata/PlasmaFreeFractionMethod.yaml
deleted file mode 100644
index cfcda719e7..0000000000
--- a/src/schema/metadata/PlasmaFreeFractionMethod.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: PlasmaFreeFractionMethod
-description: |
-  Method used to estimate free fraction.
-type: string
diff --git a/src/schema/metadata/PostLabelingDelay.yaml b/src/schema/metadata/PostLabelingDelay.yaml
deleted file mode 100644
index 8ba36f1383..0000000000
--- a/src/schema/metadata/PostLabelingDelay.yaml
+++ /dev/null
@@ -1,24 +0,0 @@
----
-name: PostLabelingDelay
-description: |
-  This is the postlabeling delay (PLD) time, in seconds, after the end of the
-  labeling (for `"CASL"` or `"PCASL"`) or middle of the labeling pulse
-  (for `"PASL"`) until the middle of the excitation pulse applied to the
-  imaging slab (for 3D acquisition) or first slice (for 2D acquisition).
-  Can be a number (for a single-PLD time series) or an array of numbers
-  (for multi-PLD and Look-Locker).
-  In the latter case, the array of numbers contains the PLD of each volume,
-  namely each `control` and `label`, in the acquisition order.
-  Any image within the time-series without a PLD, for example an `m0scan`,
-  is indicated by a zero.
-  Based on DICOM Tags 0018, 9079 `Inversion Times` and 0018, 0082
-  `InversionTime`.
-anyOf:
-  - type: number
-    exclusiveMinimum: 0
-    unit: s
-  - type: array
-    items:
-      type: number
-      exclusiveMinimum: 0
-      unit: s
diff --git a/src/schema/metadata/PowerLineFrequency.yaml b/src/schema/metadata/PowerLineFrequency.yaml
deleted file mode 100644
index da01d45b85..0000000000
--- a/src/schema/metadata/PowerLineFrequency.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: PowerLineFrequency
-description: |
-  Frequency (in Hz) of the power grid at the geographical location of the
-  instrument (for example, `50` or `60`).
-anyOf:
-  - type: number
-    exclusiveMinimum: 0
-    unit: Hz
-  - type: string
-    enum:
-      - n/a
diff --git a/src/schema/metadata/PromptRate.yaml b/src/schema/metadata/PromptRate.yaml
deleted file mode 100644
index ab2a62199c..0000000000
--- a/src/schema/metadata/PromptRate.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: PromptRate
-description: |
-  Prompt rate for each frame (same units as `Units`, for example, `"Bq/mL"`).
-type: array
-items:
-  type: number
diff --git a/src/schema/metadata/PulseSequenceDetails.yaml b/src/schema/metadata/PulseSequenceDetails.yaml
deleted file mode 100644
index 15d4b74a2e..0000000000
--- a/src/schema/metadata/PulseSequenceDetails.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: PulseSequenceDetails
-description: |
-  Information beyond pulse sequence type that identifies the specific pulse
-  sequence used (for example,
-  `"Standard Siemens Sequence distributed with the VB17 software"`,
-  `"Siemens WIP ### version #.##,"` or
-  `"Sequence written by X using a version compiled on MM/DD/YYYY"`).
-type: string
diff --git a/src/schema/metadata/PulseSequenceType.yaml b/src/schema/metadata/PulseSequenceType.yaml
deleted file mode 100644
index 89b8559547..0000000000
--- a/src/schema/metadata/PulseSequenceType.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: PulseSequenceType
-description: |
-  A general description of the pulse sequence used for the scan
-  (for example, `"MPRAGE"`, `"Gradient Echo EPI"`, `"Spin Echo EPI"`,
-  `"Multiband gradient echo EPI"`).
-type: string
diff --git a/src/schema/metadata/Purity.yaml b/src/schema/metadata/Purity.yaml
deleted file mode 100644
index 13248983a0..0000000000
--- a/src/schema/metadata/Purity.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Purity
-description: |
-  Purity of the radiolabeled compound (between 0 and 100%).
-type: number
-minimum: 0
-maximum: 100
diff --git a/src/schema/metadata/RandomRate.yaml b/src/schema/metadata/RandomRate.yaml
deleted file mode 100644
index 72e94d6f40..0000000000
--- a/src/schema/metadata/RandomRate.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: RandomRate
-description: |
-  Random rate for each frame (same units as `Units`, for example, `"Bq/mL"`).
-type: array
-items:
-  type: number
diff --git a/src/schema/metadata/RawSources.yaml b/src/schema/metadata/RawSources.yaml
deleted file mode 100644
index a9c29d2769..0000000000
--- a/src/schema/metadata/RawSources.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: RawSources
-description: |
-  A list of paths relative to dataset root pointing to the BIDS-Raw file(s)
-  that were used in the creation of this derivative.
-type: array
-items:
-  type: string
-  format: dataset_relative
diff --git a/src/schema/metadata/ReceiveCoilActiveElements.yaml b/src/schema/metadata/ReceiveCoilActiveElements.yaml
deleted file mode 100644
index 6d686329ab..0000000000
--- a/src/schema/metadata/ReceiveCoilActiveElements.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: ReceiveCoilActiveElements
-description: |
-  Information describing the active/selected elements of the receiver coil.
-  This doesn't correspond to a tag in the DICOM ontology.
-  The vendor-defined terminology for active coil elements can go in this field.
-type: string
diff --git a/src/schema/metadata/ReceiveCoilName.yaml b/src/schema/metadata/ReceiveCoilName.yaml
deleted file mode 100644
index 3d47a0e3d9..0000000000
--- a/src/schema/metadata/ReceiveCoilName.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: ReceiveCoilName
-description: |
-  Information describing the receiver coil.
-  Corresponds to DICOM Tag 0018, 1250 `Receive Coil Name`,
-  although not all vendors populate that DICOM Tag,
-  in which case this field can be derived from an appropriate
-  private DICOM field.
-type: string
diff --git a/src/schema/metadata/ReconFilterSize.yaml b/src/schema/metadata/ReconFilterSize.yaml
deleted file mode 100644
index f8d8724a08..0000000000
--- a/src/schema/metadata/ReconFilterSize.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: ReconFilterSize
-description: |
-  Kernel size of post-recon filter (FWHM) in default units `"mm"`.
-anyOf:
-  - type: number
-    unit: mm
-  - type: array
-    items:
-      type: number
-      unit: mm
diff --git a/src/schema/metadata/ReconFilterType.yaml b/src/schema/metadata/ReconFilterType.yaml
deleted file mode 100644
index 0be61d461d..0000000000
--- a/src/schema/metadata/ReconFilterType.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: ReconFilterType
-description: |
-  Type of post-recon smoothing (for example, `["Shepp"]`).
-anyOf:
-  - type: string
-  - type: array
-    items:
-      type: string
diff --git a/src/schema/metadata/ReconMethodImplementationVersion.yaml b/src/schema/metadata/ReconMethodImplementationVersion.yaml
deleted file mode 100644
index 7ed51b5ef7..0000000000
--- a/src/schema/metadata/ReconMethodImplementationVersion.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: ReconMethodImplementationVersion
-description: |
-  Identification for the software used, such as name and version.
-type: string
diff --git a/src/schema/metadata/ReconMethodName.yaml b/src/schema/metadata/ReconMethodName.yaml
deleted file mode 100644
index e6e8069de4..0000000000
--- a/src/schema/metadata/ReconMethodName.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: ReconMethodName
-description: |
-  Reconstruction method or algorithm (for example, `"3d-op-osem"`).
-type: string
diff --git a/src/schema/metadata/ReconMethodParameterLabels.yaml b/src/schema/metadata/ReconMethodParameterLabels.yaml
deleted file mode 100644
index 5b5c20f08a..0000000000
--- a/src/schema/metadata/ReconMethodParameterLabels.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: ReconMethodParameterLabels
-description: |
-  Names of reconstruction parameters (for example, `["subsets", "iterations"]`).
-type: array
-items:
-  type: string
diff --git a/src/schema/metadata/ReconMethodParameterUnits.yaml b/src/schema/metadata/ReconMethodParameterUnits.yaml
deleted file mode 100644
index 4aefc1f0c3..0000000000
--- a/src/schema/metadata/ReconMethodParameterUnits.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: ReconMethodParameterUnits
-description: |
-  Unit of reconstruction parameters (for example, `["none", "none"]`).
-type: array
-items:
-  type: string
-  format: unit
diff --git a/src/schema/metadata/ReconMethodParameterValues.yaml b/src/schema/metadata/ReconMethodParameterValues.yaml
deleted file mode 100644
index f0607b24f3..0000000000
--- a/src/schema/metadata/ReconMethodParameterValues.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: ReconMethodParameterValues
-description: |
-  Values of reconstruction parameters (for example, `[21, 3]`).
-type: array
-items:
-  type: number
diff --git a/src/schema/metadata/RecordingDuration.yaml b/src/schema/metadata/RecordingDuration.yaml
deleted file mode 100644
index 3b5986ad19..0000000000
--- a/src/schema/metadata/RecordingDuration.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: RecordingDuration
-description: |
-  Length of the recording in seconds (for example, `3600`).
-type: number
-unit: s
diff --git a/src/schema/metadata/RecordingType.yaml b/src/schema/metadata/RecordingType.yaml
deleted file mode 100644
index 138c5c4328..0000000000
--- a/src/schema/metadata/RecordingType.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: RecordingType
-description: |
-  Defines whether the recording is `"continuous"`, `"discontinuous"` or
-  `"epoched"`, where `"epoched"` is limited to time windows about events of
-  interest (for example, stimulus presentations or subject responses).
-type: string
-enum:
-  - continuous
-  - epoched
-  - discontinuous
diff --git a/src/schema/metadata/ReferencesAndLinks.yaml b/src/schema/metadata/ReferencesAndLinks.yaml
deleted file mode 100644
index 93105f671d..0000000000
--- a/src/schema/metadata/ReferencesAndLinks.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: ReferencesAndLinks
-description: |
-  List of references to publications that contain information on the dataset.
-  A reference may be textual or a
-  [URI](/02-common-principles.html#uniform-resource-indicator).
-items:
-  type: string
-type: array
diff --git a/src/schema/metadata/RepetitionTime.yaml b/src/schema/metadata/RepetitionTime.yaml
deleted file mode 100644
index 12fdbb05d2..0000000000
--- a/src/schema/metadata/RepetitionTime.yaml
+++ /dev/null
@@ -1,22 +0,0 @@
----
-name: RepetitionTime
-description: |
-  The time in seconds between the beginning of an acquisition of one volume
-  and the beginning of acquisition of the volume following it (TR).
-  When used in the context of functional acquisitions this parameter best
-  corresponds to
-  [DICOM Tag 0020, 0110](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0020,0110)):
-  the "time delta between images in a
-  dynamic of functional set of images" but may also be found in
-  [DICOM Tag 0018, 0080](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0080)):
-  "the period of time in msec between the beginning
-  of a pulse sequence and the beginning of the succeeding
-  (essentially identical) pulse sequence".
-  This definition includes time between scans (when no data has been acquired)
-  in case of sparse acquisition schemes.
-  This value MUST be consistent with the 'pixdim[4]' field (after accounting
-  for units stored in 'xyzt_units' field) in the NIfTI header.
-  This field is mutually exclusive with VolumeTiming.
-type: number
-exclusiveMinimum: 0
-unit: s
diff --git a/src/schema/metadata/RepetitionTimeExcitation.yaml b/src/schema/metadata/RepetitionTimeExcitation.yaml
deleted file mode 100644
index 192f75b7e8..0000000000
--- a/src/schema/metadata/RepetitionTimeExcitation.yaml
+++ /dev/null
@@ -1,20 +0,0 @@
----
-name: RepetitionTimeExcitation
-description: |
-  The interval, in seconds, between two successive excitations.
-  [DICOM Tag 0018, 0080](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0080)
-  best refers to this parameter.
-  This field may be used together with the `RepetitionTimePreparation` for
-  certain use cases, such as
-  [MP2RAGE](https://doi.org/10.1016/j.neuroimage.2009.10.002).
-  Use `RepetitionTimeExcitation` (in combination with
-  `RepetitionTimePreparation` if needed) for anatomy imaging data rather than
-  `RepetitionTime` as it is already defined as the amount of time that it takes
-  to acquire a single volume in the
-  [task imaging data](/04-modality-specific-files/01-magnetic-resonance-\
-  imaging-data.html#task-including-resting-state-imaging-data)
-  section.
-# TODO: Determine if this should be an anyOf (number or array of numbers)
-type: number
-minimum: 0
-unit: s
diff --git a/src/schema/metadata/RepetitionTimePreparation.yaml b/src/schema/metadata/RepetitionTimePreparation.yaml
deleted file mode 100644
index cb855edc38..0000000000
--- a/src/schema/metadata/RepetitionTimePreparation.yaml
+++ /dev/null
@@ -1,22 +0,0 @@
----
-name: RepetitionTimePreparation
-description: |
-  The interval, in seconds, that it takes a preparation pulse block to
-  re-appear at the beginning of the succeeding (essentially identical) pulse
-  sequence block.
-  The data type number may apply to files from any MRI modality concerned with
-  a single value for this field.
-  The data type array provides a value for each volume in a 4D dataset and
-  should only be used when the volume timing is critical for interpretation of
-  the data, such as in
-  [ASL](/04-modality-specific-files/01-magnetic-resonance-imaging-data.html\
-  #arterial-spin-labeling-perfusion-data).
-anyOf:
-  - type: number
-    minimum: 0
-    unit: s
-  - type: array
-    items:
-      type: number
-      minimum: 0
-      unit: s
diff --git a/src/schema/metadata/Resolution.yaml b/src/schema/metadata/Resolution.yaml
deleted file mode 100644
index 3d40a50056..0000000000
--- a/src/schema/metadata/Resolution.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: Resolution
-description: |
-  Specifies the interpretation of the resolution keyword.
-  If an object is used, then the keys should be values for the ``res`` entity
-  and values should be descriptions of those ``res`` values.
-anyOf:
-  - type: string
-  - type: object
-    additionalProperties:
-      type: string
diff --git a/src/schema/metadata/SEEGChannelCount.yaml b/src/schema/metadata/SEEGChannelCount.yaml
deleted file mode 100644
index 11c9591ee2..0000000000
--- a/src/schema/metadata/SEEGChannelCount.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: SEEGChannelCount
-description: |
-  Number of SEEG channels.
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/SampleOrigin.yaml b/src/schema/metadata/SampleOrigin.yaml
deleted file mode 100644
index 60ae73d8d8..0000000000
--- a/src/schema/metadata/SampleOrigin.yaml
+++ /dev/null
@@ -1,16 +0,0 @@
----
-name: SampleOrigin
-description: |
-  Describes from which tissue the genetic information was extracted.
-  Values MUST be one of `"blood"`, `"saliva"`, `"brain"`, `"csf"`,
-  `"breast milk"`, `"bile"`, `"amniotic fluid"`, `"other biospecimen"`.
-type: string
-enum:
-  - blood
-  - saliva
-  - brain
-  - csf
-  - breast milk
-  - bile
-  - amniotic fluid
-  - other biospecimen
diff --git a/src/schema/metadata/SamplingFrequency.yaml b/src/schema/metadata/SamplingFrequency.yaml
deleted file mode 100644
index 1cb5af600e..0000000000
--- a/src/schema/metadata/SamplingFrequency.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: SamplingFrequency
-description: |
-  Sampling frequency (in Hz) of all the data in the recording,
-  regardless of their type (for example, `2400`).
-type: number
-unit: Hz
diff --git a/src/schema/metadata/ScaleFactor.yaml b/src/schema/metadata/ScaleFactor.yaml
deleted file mode 100644
index 2cd5208b61..0000000000
--- a/src/schema/metadata/ScaleFactor.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: ScaleFactor
-description: |
-  Scale factor for each frame.
-type: array
-items:
-  type: number
diff --git a/src/schema/metadata/ScanDate.yaml b/src/schema/metadata/ScanDate.yaml
deleted file mode 100644
index 35988991cf..0000000000
--- a/src/schema/metadata/ScanDate.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: ScanDate
-description: |
-  Date of scan in the format `"YYYY-MM-DD[Z]"`.
-  This field is DEPRECATED, and this metadata SHOULD be recorded in the `acq_time` column of the
-  corresponding [Scans file](/03-modality-agnostic-files.html#scans-file).
-type: string
-pattern: date
diff --git a/src/schema/metadata/ScanOptions.yaml b/src/schema/metadata/ScanOptions.yaml
deleted file mode 100644
index bc238a1367..0000000000
--- a/src/schema/metadata/ScanOptions.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: ScanOptions
-description: |
-  Parameters of ScanningSequence.
-  Corresponds to DICOM Tag 0018, 0022 `Scan Options`.
-anyOf:
-  - type: string
-  - type: array
-    items:
-      type: string
diff --git a/src/schema/metadata/ScanStart.yaml b/src/schema/metadata/ScanStart.yaml
deleted file mode 100644
index 828df40c4a..0000000000
--- a/src/schema/metadata/ScanStart.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: ScanStart
-description: |
-  Time of start of scan with respect to `TimeZero` in the default unit seconds.
-type: number
-unit: s
diff --git a/src/schema/metadata/ScanningSequence.yaml b/src/schema/metadata/ScanningSequence.yaml
deleted file mode 100644
index f9987e2642..0000000000
--- a/src/schema/metadata/ScanningSequence.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: ScanningSequence
-description: |
-  Description of the type of data acquired.
-  Corresponds to DICOM Tag 0018, 0020 `Scanning Sequence`.
-anyOf:
-  - type: string
-  - type: array
-    items:
-      type: string
diff --git a/src/schema/metadata/ScatterFraction.yaml b/src/schema/metadata/ScatterFraction.yaml
deleted file mode 100644
index 4dac0662ba..0000000000
--- a/src/schema/metadata/ScatterFraction.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: ScatterFraction
-description: |
-  Scatter fraction for each frame (Units: 0-100%).
-type: array
-items:
-  type: number
-  minimum: 0
-  maximum: 100
diff --git a/src/schema/metadata/SequenceName.yaml b/src/schema/metadata/SequenceName.yaml
deleted file mode 100644
index f3fa8b7fc2..0000000000
--- a/src/schema/metadata/SequenceName.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: SequenceName
-description: |
-  Manufacturer's designation of the sequence name.
-  Corresponds to DICOM Tag 0018, 0024 `Sequence Name`.
-type: string
diff --git a/src/schema/metadata/SequenceVariant.yaml b/src/schema/metadata/SequenceVariant.yaml
deleted file mode 100644
index 65c53baa02..0000000000
--- a/src/schema/metadata/SequenceVariant.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: SequenceVariant
-description: |
-  Variant of the ScanningSequence.
-  Corresponds to DICOM Tag 0018, 0021 `Sequence Variant`.
-anyOf:
-  - type: string
-  - type: array
-    items:
-      type: string
diff --git a/src/schema/metadata/SinglesRate.yaml b/src/schema/metadata/SinglesRate.yaml
deleted file mode 100644
index 05c98a9aa0..0000000000
--- a/src/schema/metadata/SinglesRate.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: SinglesRate
-description: |
-  Singles rate for each frame (same units as `Units`, for example, `"Bq/mL"`).
-type: array
-items:
-  type: number
diff --git a/src/schema/metadata/SkullStripped.yaml b/src/schema/metadata/SkullStripped.yaml
deleted file mode 100644
index e4e9a60dff..0000000000
--- a/src/schema/metadata/SkullStripped.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: SkullStripped
-description: |
-  Whether the volume was skull stripped (non-brain voxels set to zero) or not.
-type: boolean
diff --git a/src/schema/metadata/SliceEncodingDirection.yaml b/src/schema/metadata/SliceEncodingDirection.yaml
deleted file mode 100644
index 76cbd611a2..0000000000
--- a/src/schema/metadata/SliceEncodingDirection.yaml
+++ /dev/null
@@ -1,23 +0,0 @@
----
-name: SliceEncodingDirection
-description: |
-  Possible values: `"i"`, `"j"`, `"k"`, `"i-"`, `"j-"`, `"k-"`
-  (the axis of the NIfTI data along which slices were acquired,
-  and the direction in which `SliceTiming` is defined with respect to).
-  `i`, `j`, `k` identifiers correspond to the first, second and third axis of
-  the data in the NIfTI file.
-  A `-` sign indicates that the contents of `SliceTiming` are defined in
-  reverse order - that is, the first entry corresponds to the slice with the
-  largest index, and the final entry corresponds to slice index zero.
-  When present, the axis defined by `SliceEncodingDirection` needs to be
-  consistent with the `slice_dim` field in the NIfTI header.
-  When absent, the entries in `SliceTiming` must be in the order of increasing
-  slice index as defined by the NIfTI header.
-type: string
-enum:
-  - i
-  - j
-  - k
-  - i-
-  - j-
-  - k-
diff --git a/src/schema/metadata/SliceTiming.yaml b/src/schema/metadata/SliceTiming.yaml
deleted file mode 100644
index 8e05e0061f..0000000000
--- a/src/schema/metadata/SliceTiming.yaml
+++ /dev/null
@@ -1,22 +0,0 @@
----
-name: SliceTiming
-description: |
-  The time at which each slice was acquired within each volume (frame) of the
-  acquisition.
-  Slice timing is not slice order -- rather, it is a list of times containing
-  the time (in seconds) of each slice acquisition in relation to the beginning
-  of volume acquisition.
-  The list goes through the slices along the slice axis in the slice encoding
-  dimension (see below).
-  Note that to ensure the proper interpretation of the `SliceTiming` field,
-  it is important to check if the OPTIONAL `SliceEncodingDirection` exists.
-  In particular, if `SliceEncodingDirection` is negative,
-  the entries in `SliceTiming` are defined in reverse order with respect to the
-  slice axis, such that the final entry in the `SliceTiming` list is the time
-  of acquisition of slice 0. Without this parameter slice time correction will
-  not be possible.
-type: array
-items:
-  type: number
-  minimum: 0
-  unit: s
diff --git a/src/schema/metadata/SoftwareFilters.yaml b/src/schema/metadata/SoftwareFilters.yaml
deleted file mode 100644
index 809b9f05fd..0000000000
--- a/src/schema/metadata/SoftwareFilters.yaml
+++ /dev/null
@@ -1,17 +0,0 @@
----
-name: SoftwareFilters
-description: |
-  [Object](https://www.json.org/json-en.html)
-  of temporal software filters applied, or `"n/a"` if the data is
-  not available.
-  Each key:value pair in the JSON object is a name of the filter and an object
-  in which its parameters are defined as key:value pairs
-  (for example, `{"Anti-aliasing filter":
-  {"half-amplitude cutoff (Hz)": 500, "Roll-off": "6dB/Octave"}}`).
-anyOf:
-  - type: object
-    additionalProperties:
-      type: object
-  - type: string
-    enum:
-      - n/a
diff --git a/src/schema/metadata/SoftwareName.yaml b/src/schema/metadata/SoftwareName.yaml
deleted file mode 100644
index 9d088f585e..0000000000
--- a/src/schema/metadata/SoftwareName.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: SoftwareName
-description: |
-  Name of the software that was used to present the stimuli.
-type: string
diff --git a/src/schema/metadata/SoftwareRRID.yaml b/src/schema/metadata/SoftwareRRID.yaml
deleted file mode 100644
index cedf4ff4ba..0000000000
--- a/src/schema/metadata/SoftwareRRID.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: SoftwareRRID
-description: |
-  [Research Resource Identifier](https://scicrunch.org/resources) of the
-  software that was used to present the stimuli.
-  Examples: The RRID for Psychtoolbox is 'SCR_002881',
-  and that of PsychoPy is 'SCR_006571'.
-type: string
-pattern: .+_.+
diff --git a/src/schema/metadata/SoftwareVersion.yaml b/src/schema/metadata/SoftwareVersion.yaml
deleted file mode 100644
index ef989b6bab..0000000000
--- a/src/schema/metadata/SoftwareVersion.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: SoftwareVersion
-description: |
-  Version of the software that was used to present the stimuli.
-type: string
diff --git a/src/schema/metadata/SoftwareVersions.yaml b/src/schema/metadata/SoftwareVersions.yaml
deleted file mode 100644
index 077a2454af..0000000000
--- a/src/schema/metadata/SoftwareVersions.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: SoftwareVersions
-description: |
-  Manufacturer's designation of software version of the equipment that produced
-  the measurements.
-type: string
diff --git a/src/schema/metadata/SourceDatasets.yaml b/src/schema/metadata/SourceDatasets.yaml
deleted file mode 100644
index 67b875e0b9..0000000000
--- a/src/schema/metadata/SourceDatasets.yaml
+++ /dev/null
@@ -1,20 +0,0 @@
----
-name: SourceDatasets
-description: |
-  Used to specify the locations and relevant attributes of all source datasets.
-  Valid keys in each object include `URL`, `DOI` (see
-  [URI](/02-common-principles.html#uniform-resource-indicator)), and
-  `Version` with
-  [string](https://www.w3schools.com/js/js_json_datatypes.asp)
-  values.
-type: array
-items:
-  type: object
-  properties:
-    URL:
-      type: string
-      format: uri
-    DOI:
-      type: string
-    Version:
-      type: string
diff --git a/src/schema/metadata/Sources.yaml b/src/schema/metadata/Sources.yaml
deleted file mode 100644
index 5d7d4de428..0000000000
--- a/src/schema/metadata/Sources.yaml
+++ /dev/null
@@ -1,15 +0,0 @@
----
-name: Sources
-description: |
-  A list of files with the paths specified relative to dataset root;
-  these files were directly used in the creation of this derivative data file.
-  For example, if a derivative A is used in the creation of another
-  derivative B, which is in turn used to generate C in a chain of A->B->C,
-  C should only list B in `Sources`, and B should only list A in `Sources`.
-  However, in case both X and Y are directly used in the creation of Z,
-  then Z should list X and Y in `Sources`,
-  regardless of whether X was used to generate Y.
-type: array
-items:
-  type: string
-  format: dataset_relative
diff --git a/src/schema/metadata/SpatialReference.yaml b/src/schema/metadata/SpatialReference.yaml
deleted file mode 100644
index 15b2a3d947..0000000000
--- a/src/schema/metadata/SpatialReference.yaml
+++ /dev/null
@@ -1,24 +0,0 @@
----
-name: SpatialReference
-description: |
-  For images with a single reference, the value MUST be a single string.
-  For images with multiple references, such as surface and volume references,
-  a JSON object MUST be used.
-anyOf:
-  - type: string
-    enum:
-      - orig
-  - type: string
-    format: uri
-  - type: string
-    format: dataset_relative
-  - type: object
-    additionalProperties:
-      anyOf:
-        - type: string
-          enum:
-            - orig
-        - type: string
-          format: uri
-        - type: string
-          format: dataset_relative
diff --git a/src/schema/metadata/SpecificRadioactivity.yaml b/src/schema/metadata/SpecificRadioactivity.yaml
deleted file mode 100644
index de3e978e0f..0000000000
--- a/src/schema/metadata/SpecificRadioactivity.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: SpecificRadioactivity
-description: |
-  Specific activity of compound injected.
-  **Note this is not required for an FDG acquisition, since it is not available,
-  and SHOULD be set to `"n/a"`**.
-anyOf:
-  - type: number
-  - type: string
-    enum:
-      - n/a
diff --git a/src/schema/metadata/SpecificRadioactivityMeasTime.yaml b/src/schema/metadata/SpecificRadioactivityMeasTime.yaml
deleted file mode 100644
index fdf674b06e..0000000000
--- a/src/schema/metadata/SpecificRadioactivityMeasTime.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: SpecificRadioactivityMeasTime
-description: |
-  Time to which specific radioactivity measurement above applies in the default
-  unit `"hh:mm:ss"`.
-type: string
-pattern: ^(?:2[0-3]|[01][0-9]):[0-5][0-9]:[0-5][0-9]$
diff --git a/src/schema/metadata/SpecificRadioactivityUnits.yaml b/src/schema/metadata/SpecificRadioactivityUnits.yaml
deleted file mode 100644
index e352aafdc4..0000000000
--- a/src/schema/metadata/SpecificRadioactivityUnits.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: SpecificRadioactivityUnits
-description: |
-  Unit format of specified specific radioactivity (for example, `"Bq/g"`).
-  **Note this is not required for an FDG acquisition, since it is not available,
-  and SHOULD be set to `"n/a"`**.
-anyOf:
-  - type: string
-    format: unit
-  - type: string
-    enum:
-      - n/a
diff --git a/src/schema/metadata/SpoilingGradientDuration.yaml b/src/schema/metadata/SpoilingGradientDuration.yaml
deleted file mode 100644
index feefc38e4e..0000000000
--- a/src/schema/metadata/SpoilingGradientDuration.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: SpoilingGradientDuration
-description: |
-  The duration of the spoiler gradient lobe in seconds.
-  The duration of a trapezoidal lobe is defined as the summation of ramp-up
-  and plateau times.
-type: number
-unit: s
diff --git a/src/schema/metadata/SpoilingGradientMoment.yaml b/src/schema/metadata/SpoilingGradientMoment.yaml
deleted file mode 100644
index 0735b2297f..0000000000
--- a/src/schema/metadata/SpoilingGradientMoment.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: SpoilingGradientMoment
-description: |
-  Zeroth moment of the spoiler gradient lobe in
-  millitesla times second per meter (mT.s/m).
-type: number
-unit: mT.s/m
diff --git a/src/schema/metadata/SpoilingRFPhaseIncrement.yaml b/src/schema/metadata/SpoilingRFPhaseIncrement.yaml
deleted file mode 100644
index 7daaeff393..0000000000
--- a/src/schema/metadata/SpoilingRFPhaseIncrement.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: SpoilingRFPhaseIncrement
-description: |
-  The amount of incrementation described in degrees,
-  which is applied to the phase of the excitation pulse at each TR period for
-  achieving RF spoiling.
-type: number
-unit: degrees
diff --git a/src/schema/metadata/SpoilingState.yaml b/src/schema/metadata/SpoilingState.yaml
deleted file mode 100644
index 0cdba3b490..0000000000
--- a/src/schema/metadata/SpoilingState.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: SpoilingState
-description: |
-  Boolean stating whether the pulse sequence uses any type of spoiling
-  strategy to suppress residual transverse magnetization.
-type: boolean
diff --git a/src/schema/metadata/SpoilingType.yaml b/src/schema/metadata/SpoilingType.yaml
deleted file mode 100644
index 2c533cba31..0000000000
--- a/src/schema/metadata/SpoilingType.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: SpoilingType
-description: |
-  Specifies which spoiling method(s) are used by a spoiled sequence.
-  Accepted values: `"RF"`, `"GRADIENT"` or `"COMBINED"`.
-type: string
-enum:
-  - RF
-  - GRADIENT
-  - COMBINED
diff --git a/src/schema/metadata/StartTime.yaml b/src/schema/metadata/StartTime.yaml
deleted file mode 100644
index e9fc931107..0000000000
--- a/src/schema/metadata/StartTime.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: StartTime
-description: |
-  Start time in seconds in relation to the start of acquisition of the first
-  data sample in the corresponding neural dataset (negative values are allowed).
-type: number
-unit: s
diff --git a/src/schema/metadata/StationName.yaml b/src/schema/metadata/StationName.yaml
deleted file mode 100644
index 69e81783ed..0000000000
--- a/src/schema/metadata/StationName.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: StationName
-description: |
-  Institution defined name of the machine that produced the measurements.
-  Corresponds to DICOM Tag 0008, 1010 `Station Name`.
-type: string
diff --git a/src/schema/metadata/StimulusPresentation.yaml b/src/schema/metadata/StimulusPresentation.yaml
deleted file mode 100644
index f58419ea3e..0000000000
--- a/src/schema/metadata/StimulusPresentation.yaml
+++ /dev/null
@@ -1,20 +0,0 @@
----
-name: StimulusPresentation
-description: |
-  Object containing key value pairs related to the software used to present
-  the stimuli during the experiment, specifically:
-  `OperatingSystem`, `SoftwareName`, `SoftwareRRID`, `SoftwareVersion` and
-  `Code`.
-  See table below for more information.
-type: object
-properties:
-  OperatingSystem:
-    $ref: OperatingSystem.yaml
-  SoftwareName:
-    $ref: SoftwareName.yaml
-  SoftwareRRID:
-    $ref: SoftwareRRID.yaml
-  SoftwareVersion:
-    $ref: SoftwareVersion.yaml
-  Code:
-    $ref: Code.yaml
diff --git a/src/schema/metadata/SubjectArtefactDescription.yaml b/src/schema/metadata/SubjectArtefactDescription.yaml
deleted file mode 100644
index 3653693089..0000000000
--- a/src/schema/metadata/SubjectArtefactDescription.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: SubjectArtefactDescription
-description: |
-  Freeform description of the observed subject artefact and its possible cause
-  (for example, `"Vagus Nerve Stimulator"`, `"non-removable implant"`).
-  If this field is set to `"n/a"`, it will be interpreted as absence of major
-  source of artifacts except cardiac and blinks.
-type: string
diff --git a/src/schema/metadata/TaskDescription.yaml b/src/schema/metadata/TaskDescription.yaml
deleted file mode 100644
index f752c09997..0000000000
--- a/src/schema/metadata/TaskDescription.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: TaskDescription
-description: |
-  Longer description of the task.
-type: string
diff --git a/src/schema/metadata/TaskName.yaml b/src/schema/metadata/TaskName.yaml
deleted file mode 100644
index a6b29928ca..0000000000
--- a/src/schema/metadata/TaskName.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: TaskName
-description: |
-  Name of the task.
-  No two tasks should have the same name.
-  The task label included in the file name is derived from this TaskName field
-  by removing all non-alphanumeric (`[a-zA-Z0-9]`) characters.
-  For example `TaskName` `"faces n-back"` will correspond to task label
-  `facesnback`.
-type: string
diff --git a/src/schema/metadata/TermURL.yaml b/src/schema/metadata/TermURL.yaml
deleted file mode 100644
index e551c12311..0000000000
--- a/src/schema/metadata/TermURL.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: TermURL
-description: |
-  URL pointing to a formal definition of this type of data in an ontology
-  available on the web.
-type: string
diff --git a/src/schema/metadata/TimeZero.yaml b/src/schema/metadata/TimeZero.yaml
deleted file mode 100644
index 79fc73ea18..0000000000
--- a/src/schema/metadata/TimeZero.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: TimeZero
-description: |
-  Time zero to which all scan and/or blood measurements have been adjusted to,
-  in the unit "hh:mm:ss".
-  This should be equal to `InjectionStart` or `ScanStart`.
-type: string
-pattern: ^(?:2[0-3]|[01][0-9]):[0-5][0-9]:[0-5][0-9]$
diff --git a/src/schema/metadata/TissueOrigin.yaml b/src/schema/metadata/TissueOrigin.yaml
deleted file mode 100644
index 3bb8b3a607..0000000000
--- a/src/schema/metadata/TissueOrigin.yaml
+++ /dev/null
@@ -1,14 +0,0 @@
----
-name: TissueOrigin
-description: |
-  Describes the type of tissue analyzed for `SampleOrigin` `brain`.
-  Values MUST be one of `"gray matter"`, `"white matter"`, `"csf"`,
-  `"meninges"`, `"macrovascular"` or `microvascular`.
-type: string
-enum:
-  - gray matter
-  - white matter
-  - csf
-  - meninges
-  - macrovascular
-  - microvascular
diff --git a/src/schema/metadata/TotalAcquiredPairs.yaml b/src/schema/metadata/TotalAcquiredPairs.yaml
deleted file mode 100644
index cb51364347..0000000000
--- a/src/schema/metadata/TotalAcquiredPairs.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: TotalAcquiredPairs
-description: |
-  The total number of acquired `control`-`label` pairs.
-  A single pair consists of a single `control` and a single `label` image.
-type: number
-exclusiveMinimum: 0
diff --git a/src/schema/metadata/TotalReadoutTime.yaml b/src/schema/metadata/TotalReadoutTime.yaml
deleted file mode 100644
index afb9531f62..0000000000
--- a/src/schema/metadata/TotalReadoutTime.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: TotalReadoutTime
-description: |
-  This is actually the "effective" total readout time,
-  defined as the readout duration, specified in seconds,
-  that would have generated data with the given level of distortion.
-  It is NOT the actual, physical duration of the readout train.
-  If `EffectiveEchoSpacing` has been properly computed,
-  it is just `EffectiveEchoSpacing * (ReconMatrixPE - 1)`.
-type: number
-unit: s
diff --git a/src/schema/metadata/TracerMolecularWeight.yaml b/src/schema/metadata/TracerMolecularWeight.yaml
deleted file mode 100644
index 5b12539676..0000000000
--- a/src/schema/metadata/TracerMolecularWeight.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: TracerMolecularWeight
-description: |
-  Accurate molecular weight of the tracer used.
-type: number
diff --git a/src/schema/metadata/TracerMolecularWeightUnits.yaml b/src/schema/metadata/TracerMolecularWeightUnits.yaml
deleted file mode 100644
index 09ad40b624..0000000000
--- a/src/schema/metadata/TracerMolecularWeightUnits.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: TracerMolecularWeightUnits
-description: |
-  Unit of the molecular weights measurement (for example, `"g/mol"`).
-type: string
-format: unit
diff --git a/src/schema/metadata/TracerName.yaml b/src/schema/metadata/TracerName.yaml
deleted file mode 100644
index 307757d3f4..0000000000
--- a/src/schema/metadata/TracerName.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: TracerName
-description: |
-  Name of the tracer compound used (for example, `"CIMBI-36"`)
-type: string
diff --git a/src/schema/metadata/TracerRadLex.yaml b/src/schema/metadata/TracerRadLex.yaml
deleted file mode 100644
index f373e8074b..0000000000
--- a/src/schema/metadata/TracerRadLex.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: TracerRadLex
-description: |
-  ID of the tracer compound from the RadLex Ontology.
-type: string
diff --git a/src/schema/metadata/TracerRadionuclide.yaml b/src/schema/metadata/TracerRadionuclide.yaml
deleted file mode 100644
index af66d28638..0000000000
--- a/src/schema/metadata/TracerRadionuclide.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: TracerRadionuclide
-description: |
-  Radioisotope labelling tracer (for example, `"C11"`).
-type: string
diff --git a/src/schema/metadata/TracerSNOMED.yaml b/src/schema/metadata/TracerSNOMED.yaml
deleted file mode 100644
index 514ba18bde..0000000000
--- a/src/schema/metadata/TracerSNOMED.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: TracerSNOMED
-description: |
-  ID of the tracer compound from the SNOMED Ontology
-  (subclass of Radioactive isotope).
-type: string
diff --git a/src/schema/metadata/TriggerChannelCount.yaml b/src/schema/metadata/TriggerChannelCount.yaml
deleted file mode 100644
index 920bc25f15..0000000000
--- a/src/schema/metadata/TriggerChannelCount.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: TriggerChannelCount
-description: |
-  Number of channels for digital (TTL bit level) triggers.
-type: integer
-minimum: 0
diff --git a/src/schema/metadata/TubingLength.yaml b/src/schema/metadata/TubingLength.yaml
deleted file mode 100644
index a101f98653..0000000000
--- a/src/schema/metadata/TubingLength.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: TubingLength
-description: |
-  The length of the blood tubing, from the subject to the detector in meters.
-type: number
-unit: m
diff --git a/src/schema/metadata/TubingType.yaml b/src/schema/metadata/TubingType.yaml
deleted file mode 100644
index 70961e086d..0000000000
--- a/src/schema/metadata/TubingType.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: TubingType
-description: |
-  Description of the type of tubing used, ideally including the material and
-  (internal) diameter.
-type: string
diff --git a/src/schema/metadata/Type.yaml b/src/schema/metadata/Type.yaml
deleted file mode 100644
index 4aa47ecaf7..0000000000
--- a/src/schema/metadata/Type.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: Type
-description: |
-  Short identifier of the mask.
-  Reserved values: `Brain` - brain mask, `Lesion` - lesion mask,
-  `Face` - face mask, `ROI` - ROI mask
-type: string
-enum:
-  - Brain
-  - Lesion
-  - Face
-  - ROI
diff --git a/src/schema/metadata/Units.yaml b/src/schema/metadata/Units.yaml
deleted file mode 100644
index 82ab2ccc2f..0000000000
--- a/src/schema/metadata/Units.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: Units
-description: |
-  Measurement units for the associated file.
-  SI units in CMIXF formatting are RECOMMENDED
-  (see [Units](/02-common-principles.html#units)).
-type: string
-format: unit
diff --git a/src/schema/metadata/VascularCrushing.yaml b/src/schema/metadata/VascularCrushing.yaml
deleted file mode 100644
index faeb93872a..0000000000
--- a/src/schema/metadata/VascularCrushing.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: VascularCrushing
-description: |
-  Boolean indicating if Vascular Crushing is used.
-  Corresponds to DICOM Tag 0018, 9259 `ASL Crusher Flag`.
-type: boolean
diff --git a/src/schema/metadata/VascularCrushingVENC.yaml b/src/schema/metadata/VascularCrushingVENC.yaml
deleted file mode 100644
index bbda6ad57a..0000000000
--- a/src/schema/metadata/VascularCrushingVENC.yaml
+++ /dev/null
@@ -1,15 +0,0 @@
----
-name: VascularCrushingVENC
-description: |
-  The crusher gradient strength, in centimeters per second.
-  Specify either one number for the total time-series, or provide an array of
-  numbers, for example when using QUASAR, using the value zero to identify
-  volumes for which `VascularCrushing` was turned off.
-  Corresponds to DICOM Tag 0018, 925A `ASL Crusher Flow Limit`.
-anyOf:
-  - type: number
-    unit: cm/s
-  - type: array
-    items:
-      type: number
-      unit: cm/s
diff --git a/src/schema/metadata/VolumeTiming.yaml b/src/schema/metadata/VolumeTiming.yaml
deleted file mode 100644
index 82d3e08486..0000000000
--- a/src/schema/metadata/VolumeTiming.yaml
+++ /dev/null
@@ -1,16 +0,0 @@
----
-name: VolumeTiming
-description: |
-  The time at which each volume was acquired during the acquisition.
-  It is described using a list of times referring to the onset of each volume
-  in the BOLD series.
-  The list must have the same length as the BOLD series,
-  and the values must be non-negative and monotonically increasing.
-  This field is mutually exclusive with `RepetitionTime` and `DelayTime`.
-  If defined, this requires acquisition time (TA) be defined via either
-  `SliceTiming` or `AcquisitionDuration` be defined.
-type: array
-minItems: 1
-items:
-  type: number
-  unit: s
diff --git a/src/schema/metadata/WholeBloodAvail.yaml b/src/schema/metadata/WholeBloodAvail.yaml
deleted file mode 100644
index b4ac2defb5..0000000000
--- a/src/schema/metadata/WholeBloodAvail.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: WholeBloodAvail
-description: |
-  Boolean that specifies if whole blood measurements are available.
-  If `true`, the `whole_blood_radioactivity` column MUST be present in the
-  corresponding `*_blood.tsv` file.
-type: boolean
diff --git a/src/schema/metadata/WithdrawalRate.yaml b/src/schema/metadata/WithdrawalRate.yaml
deleted file mode 100644
index c26fa1fdc8..0000000000
--- a/src/schema/metadata/WithdrawalRate.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: WithdrawalRate
-description: |
-  The rate at which the blood was withdrawn from the subject.
-  The unit of the specified withdrawal rate should be in `"mL/s"`.
-type: number
-unit: mL/s
diff --git a/src/schema/metadata/_CoordUnits.yaml b/src/schema/metadata/_CoordUnits.yaml
deleted file mode 100644
index ed39f77d0e..0000000000
--- a/src/schema/metadata/_CoordUnits.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-type: string
-enum:
-  - m
-  - mm
-  - cm
-  - n/a
diff --git a/src/schema/metadata/_EEGCoordSys.yaml b/src/schema/metadata/_EEGCoordSys.yaml
deleted file mode 100644
index a24d7e7eff..0000000000
--- a/src/schema/metadata/_EEGCoordSys.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-type: string
-enum:
-  - CapTrak
-  - EEGLAB
-  - EEGLAB-HJ
-  - Other
diff --git a/src/schema/metadata/_GeneticLevelEnum.yaml b/src/schema/metadata/_GeneticLevelEnum.yaml
deleted file mode 100644
index 649e6ab2fb..0000000000
--- a/src/schema/metadata/_GeneticLevelEnum.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-type: string
-enum:
-  - Genetic
-  - Genomic
-  - Epigenomic
-  - Transcriptomic
-  - Metabolomic
-  - Proteomic
diff --git a/src/schema/metadata/_LandmarkCoordinates.yaml b/src/schema/metadata/_LandmarkCoordinates.yaml
deleted file mode 100644
index 0a04695f55..0000000000
--- a/src/schema/metadata/_LandmarkCoordinates.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-type: object
-additionalProperties:
-  type: array
-  items:
-    type: number
-  minItems: 3
-  maxItems: 3
diff --git a/src/schema/metadata/_MEGCoordSys.yaml b/src/schema/metadata/_MEGCoordSys.yaml
deleted file mode 100644
index ca8cbfe369..0000000000
--- a/src/schema/metadata/_MEGCoordSys.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-type: string
-enum:
-  - CTF
-  - ElektaNeuromag
-  - 4DBti
-  - KitYokogawa
-  - ChietiItab
-  - Other
diff --git a/src/schema/metadata/_StandardTemplateCoordSys.yaml b/src/schema/metadata/_StandardTemplateCoordSys.yaml
deleted file mode 100644
index 9b58b245e3..0000000000
--- a/src/schema/metadata/_StandardTemplateCoordSys.yaml
+++ /dev/null
@@ -1,25 +0,0 @@
----
-type: string
-enum:
-  - ICBM452AirSpace
-  - ICBM452Warp5Space
-  - IXI549Space
-  - fsaverage
-  - fsaverageSym
-  - fsLR
-  - MNIColin27
-  - MNI152Lin
-  - MNI152NLin2009aSym
-  - MNI152NLin2009bSym
-  - MNI152NLin2009cSym
-  - MNI152NLin2009aAsym
-  - MNI152NLin2009bAsym
-  - MNI152NLin2009cAsym
-  - MNI152NLin6Sym
-  - MNI152NLin6ASym
-  - MNI305
-  - NIHPD
-  - OASIS30AntsOASISAnts
-  - OASIS30Atropos
-  - Talairach
-  - UNCInfant
diff --git a/src/schema/metadata/_StandardTemplateDeprecatedCoordSys.yaml b/src/schema/metadata/_StandardTemplateDeprecatedCoordSys.yaml
deleted file mode 100644
index 7a2a7c4c6e..0000000000
--- a/src/schema/metadata/_StandardTemplateDeprecatedCoordSys.yaml
+++ /dev/null
@@ -1,17 +0,0 @@
----
-type: string
-enum:
-  - fsaverage3
-  - fsaverage4
-  - fsaverage5
-  - fsaverage6
-  - fsaveragesym
-  - UNCInfant0V21
-  - UNCInfant1V21
-  - UNCInfant2V21
-  - UNCInfant0V22
-  - UNCInfant1V22
-  - UNCInfant2V22
-  - UNCInfant0V23
-  - UNCInfant1V23
-  - UNCInfant2V23
diff --git a/src/schema/metadata/_iEEGCoordSys.yaml b/src/schema/metadata/_iEEGCoordSys.yaml
deleted file mode 100644
index 99d3d82d8c..0000000000
--- a/src/schema/metadata/_iEEGCoordSys.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-type: string
-enum:
-  - Pixels
-  - ACPC
-  - ScanRAS
-  - Other
diff --git a/src/schema/metadata/_template.yaml b/src/schema/metadata/_template.yaml
deleted file mode 100644
index 43e890c784..0000000000
--- a/src/schema/metadata/_template.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name:
-description:
-type:
-unit:
diff --git a/src/schema/metadata/iEEGCoordinateProcessingDescription.yaml b/src/schema/metadata/iEEGCoordinateProcessingDescription.yaml
deleted file mode 100644
index 1a8c5f95ed..0000000000
--- a/src/schema/metadata/iEEGCoordinateProcessingDescription.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: iEEGCoordinateProcessingDescription
-description: |
-  Has any post-processing (such as projection) been done on the electrode
-  positions (for example, `"surface_projection"`, `"none"`).
-type: string
diff --git a/src/schema/metadata/iEEGCoordinateProcessingReference.yaml b/src/schema/metadata/iEEGCoordinateProcessingReference.yaml
deleted file mode 100644
index ba8b31c6cc..0000000000
--- a/src/schema/metadata/iEEGCoordinateProcessingReference.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: iEEGCoordinateProcessingReference
-description: |
-  A reference to a paper that defines in more detail the method used to
-  localize the electrodes and to post-process the electrode positions.
-type: string
diff --git a/src/schema/metadata/iEEGCoordinateSystem.yaml b/src/schema/metadata/iEEGCoordinateSystem.yaml
deleted file mode 100644
index 24ce59b540..0000000000
--- a/src/schema/metadata/iEEGCoordinateSystem.yaml
+++ /dev/null
@@ -1,19 +0,0 @@
----
-name: iEEGCoordinateSystem
-description: |
-  Defines the coordinate system for the iEEG sensors.
-  See
-  [Appendix VIII](/99-appendices/08-coordinate-systems.html)
-  for a list of restricted keywords for coordinate systems.
-  If `"Other"`, provide definition of the coordinate system in
-  `iEEGCoordinateSystemDescription`.
-  If positions correspond to pixel indices in a 2D image
-  (of either a volume-rendering, surface-rendering, operative photo, or
-  operative drawing), this MUST be `"Pixels"`.
-  For more information, see the section on
-  [2D coordinate systems](/04-modality-specific-files/04-intracranial\
-  -electroencephalography.html#allowed-2d-coordinate-systems).
-anyOf:
-  - $ref: _iEEGCoordSys.yaml
-  - $ref: _StandardTemplateCoordSys.yaml
-  - $ref: _StandardTemplateDeprecatedCoordSys.yaml
diff --git a/src/schema/metadata/iEEGCoordinateSystemDescription.yaml b/src/schema/metadata/iEEGCoordinateSystemDescription.yaml
deleted file mode 100644
index f50387ed12..0000000000
--- a/src/schema/metadata/iEEGCoordinateSystemDescription.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: iEEGCoordinateSystemDescription
-description: |
-  Free-form text description of the coordinate system.
-  May also include a link to a documentation page or paper describing the
-  system in greater detail.
-type: string
diff --git a/src/schema/metadata/iEEGCoordinateUnits.yaml b/src/schema/metadata/iEEGCoordinateUnits.yaml
deleted file mode 100644
index 57b3bc7027..0000000000
--- a/src/schema/metadata/iEEGCoordinateUnits.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: iEEGCoordinateUnits
-description: |
-  Units of the `*_electrodes.tsv`, MUST be `"m"`, `"mm"`, `"cm"` or `"pixels"`.
-  MUST be `"pixels"` if `iEEGCoordinateSystem` is `Pixels`.
-type: string
-enum:
-  - m
-  - mm
-  - cm
-  - pixels
-  - n/a
diff --git a/src/schema/metadata/iEEGElectrodeGroups.yaml b/src/schema/metadata/iEEGElectrodeGroups.yaml
deleted file mode 100644
index 73a173b36a..0000000000
--- a/src/schema/metadata/iEEGElectrodeGroups.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: iEEGElectrodeGroups
-description: |
-  Field to describe the way electrodes are grouped into strips, grids or depth
-  probes.
-  For example, `"grid1: 10x8 grid on left temporal pole, strip2: 1x8 electrode
-  strip on xxx"`.
-type: string
diff --git a/src/schema/metadata/iEEGGround.yaml b/src/schema/metadata/iEEGGround.yaml
deleted file mode 100644
index cf5e86e5cb..0000000000
--- a/src/schema/metadata/iEEGGround.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: iEEGGround
-description: |
-  Description of the location of the ground electrode
-  (`"placed on right mastoid (M2)"`).
-type: string
diff --git a/src/schema/metadata/iEEGPlacementScheme.yaml b/src/schema/metadata/iEEGPlacementScheme.yaml
deleted file mode 100644
index 913b8d3662..0000000000
--- a/src/schema/metadata/iEEGPlacementScheme.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: iEEGPlacementScheme
-description: |
-  Freeform description of the placement of the iEEG electrodes.
-  Left/right/bilateral/depth/surface
-  (for example, `"left frontal grid and bilateral hippocampal depth"` or
-  `"surface strip and STN depth"` or
-  `"clinical indication bitemporal, bilateral temporal strips and left grid"`).
-type: string
diff --git a/src/schema/metadata/iEEGReference.yaml b/src/schema/metadata/iEEGReference.yaml
deleted file mode 100644
index 54180b846d..0000000000
--- a/src/schema/metadata/iEEGReference.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
----
-name: iEEGReference
-description: |
-  General description of the reference scheme used and (when applicable) of
-  location of the reference electrode in the raw recordings
-  (for example, `"left mastoid"`, `"bipolar"`,
-  `"T01"` for electrode with name T01,
-  `"intracranial electrode on top of a grid, not included with data"`,
-  `"upside down electrode"`).
-  If different channels have a different reference,
-  this field should have a general description and the channel specific
-  reference should be defined in the channels.tsv file.
-type: string
diff --git a/src/schema/modalities.yaml b/src/schema/modalities.yaml
deleted file mode 100644
index 017d6de167..0000000000
--- a/src/schema/modalities.yaml
+++ /dev/null
@@ -1,29 +0,0 @@
----
-mri:
-  name: Magnetic Resonance Imaging
-  datatypes:
-    - anat
-    - dwi
-    - fmap
-    - func
-    - perf
-eeg:
-  name: Electroencephalography
-  datatypes:
-    - eeg
-ieeg:
-  name: Intracranial Electroencephalography
-  datatypes:
-    - ieeg
-meg:
-  name: Magnetoencephalography
-  datatypes:
-    - meg
-beh:
-  name: Behavioral experiments
-  datatypes:
-    - beh
-pet:
-  name: Positron Emission Tomography
-  datatypes:
-    - pet
diff --git a/src/schema/objects/associated_data.yaml b/src/schema/objects/associated_data.yaml
new file mode 100644
index 0000000000..50fa80247c
--- /dev/null
+++ b/src/schema/objects/associated_data.yaml
@@ -0,0 +1,28 @@
+---
+# This file describes folders that may appear within a dataset folder
+# without following BIDS rules.
+# Information about whether these folders are required or not is present in
+# `rules/associated_data.yaml`.
+code:
+  name: Code
+  description: |
+    A folder in which to store any code used to generate the derivatives from the
+    source data.
+derivatives:
+  name: Derivative data
+  description:
+sourcedata:
+  name: Source data
+  description: |
+    Data before harmonization, reconstruction, and/or file format conversion
+    (for example, E-Prime event logs or DICOM files).
+stimuli:
+  name: Stimulus files
+  description: |
+    The stimulus files can be added in a `/stimuli` folder
+    (under the root folder of the dataset; with optional subfolders)
+    AND using a stim_file column in *_events.tsv mentioning which stimulus file was
+    used for a given event.
+
+    There are no restrictions on the file formats of the stimuli files, but they should be
+    stored in the `/stimuli` folder.
diff --git a/src/schema/objects/datatypes.yaml b/src/schema/objects/datatypes.yaml
new file mode 100644
index 0000000000..f17e8feb9f
--- /dev/null
+++ b/src/schema/objects/datatypes.yaml
@@ -0,0 +1,40 @@
+---
+# This file defines valid BIDS datatypes, along with their full names and descriptions.
+# For rules regarding how suffixes relate to datatypes, see files in `rules/datatypes/`.
+anat:
+  name: Anatomical Magnetic Resonance Imaging
+  description: |
+    Magnetic resonance imaging sequences designed to characterize static, anatomical features.
+beh:
+  name: Behavioral Data
+  description: |
+    Behavioral data.
+dwi:
+  name: Diffusion-Weighted Imaging
+  description: |
+    Diffusion-weighted imaging (DWI).
+eeg:
+  name: Electroencephalography
+  description: Electroencephalography
+fmap:
+  name: Field maps
+  description: |
+    MRI scans for estimating B0 inhomogeneity-induced distortions.
+func:
+  name: Task-Based Magnetic Resonance Imaging
+  description: |
+    Task (including resting state) imaging data
+ieeg:
+  name: Intracranial electroencephalography
+  description: |
+    Intracranial electroencephalography (iEEG) or electrocorticography (ECoG) data
+meg:
+  name: Magnetoencephalography
+  description: Magnetoencephalography
+perf:
+  name: Perfusion imaging
+  description: |
+    Blood perfusion imaging data, including arterial spin labeling (ASL)
+pet:
+  name: Positron Emission Tomography
+  description:
diff --git a/src/schema/entities.yaml b/src/schema/objects/entities.yaml
similarity index 95%
rename from src/schema/entities.yaml
rename to src/schema/objects/entities.yaml
index 8bcd1a16c1..b5d4339d68 100644
--- a/src/schema/entities.yaml
+++ b/src/schema/objects/entities.yaml
@@ -1,53 +1,8 @@
 ---
-subject:
-  name: Subject
-  entity: sub
-  description: |
-    A person or animal participating in the study.
-  type: string
-  format: label
-session:
-  name: Session
-  entity: ses
-  description: |
-    A logical grouping of neuroimaging and behavioral data consistent across
-    subjects.
-    Session can (but doesn't have to) be synonymous to a visit in a
-    longitudinal study.
-    In general, subjects will stay in the scanner during one session.
-    However, for example, if a subject has to leave the scanner room and then
-    be re-positioned on the scanner bed, the set of MRI acquisitions will still
-    be considered as a session and match sessions acquired in other subjects.
-    Similarly, in situations where different data types are obtained over
-    several visits (for example fMRI on one day followed by DWI the day after)
-    those can be grouped in one session.
-    Defining multiple sessions is appropriate when several identical or similar
-    data acquisitions are planned and performed on all -or most- subjects,
-    often in the case of some intervention between sessions
-    (for example, training).
-  type: string
-  format: label
-sample:
-  name: Sample
-  entity: sample
-  description: |
-    A sample pertaining to a subject such as tissue, primary cell
-    or cell-free sample.
-    The `sample-<label>` key/value pair is used to distinguish between different
-    samples from the same subject.
-    The label MUST be unique per subject and is RECOMMENDED to be unique
-    throughout the dataset.
-  format: label
-task:
-  name: Task
-  entity: task
-  description: |
-    Each task has a unique label that MUST only consist of letters and/or
-    numbers (other characters, including spaces and underscores, are not
-    allowed).
-    Those labels MUST be consistent across subjects and sessions.
-  type: string
-  format: label
+# This file describes entities present in BIDS filenames.
+# WARNING: The entities are presented here in alphabetical order!
+# The appropriate order of entities in filenames is defined in `rules/entities.yaml`,
+# rather than this file (`objects/entities.yaml`).
 acquisition:
   name: Acquisition
   entity: acq
@@ -81,23 +36,25 @@ ceagent:
     with the same label.
   type: string
   format: label
-tracer:
-  name: Tracer
-  entity: trc
+density:
+  name: Density
+  entity: den
   description: |
-    The `trc-<label>` key/value can be used to distinguish
-    sequences using different tracers.
-    The key `TracerName` MUST also be included in the associated JSON file,
-    although the label may be different.
+    Density of non-parametric surfaces.
+    MUST have a corresponding `Density` metadata field to provide
+    interpretation.
+
+    This entity is only applicable to derivative data.
   type: string
   format: label
-reconstruction:
-  name: Reconstruction
-  entity: rec
+description:
+  name: Description
+  entity: desc
   description: |
-    The `rec-<label>` key/value can be used to distinguish
-    different reconstruction algorithms (for example ones using motion
-    correction).
+    When necessary to distinguish two files that do not otherwise have a
+    distinguishing entity, the `_desc-<label>` keyword-value SHOULD be used.
+
+    This entity is only applicable to derivative data.
   type: string
   format: label
 direction:
@@ -109,31 +66,6 @@ direction:
     directions.
   type: string
   format: label
-run:
-  name: Run
-  entity: run
-  description: |
-    If several scans with the same acquisition parameters are acquired in the same session,
-    they MUST be indexed with the [`run-<index>`](../99-appendices/09-entities.md#run) entity:
-    `_run-1`, `_run-2`, `_run-3`, and so on (only nonnegative integers are allowed as
-    run labels).
-
-    If different entities apply,
-    such as a different session indicated by [`ses-<label>`](../99-appendices/09-entities.md#ses),
-    or different acquisition parameters indicated by
-    [`acq-<label>`](../99-appendices/09-entities.md#acq),
-    then `run` is not needed to distinguish the scans and MAY be omitted.
-  type: string
-  format: index
-modality:
-  name: Corresponding Modality
-  entity: mod
-  description: |
-    The `mod-<label>` key/value pair corresponds to modality label for defacing
-    masks, for example, T1w, inplaneT1, referenced by a defacemask image.
-    For example, `sub-01_mod-T1w_defacemask.nii.gz`.
-  type: string
-  format: label
 echo:
   name: Echo
   entity: echo
@@ -171,6 +103,26 @@ inversion:
     value which needs to be stored in the field `InversionTime` of the separate JSON file.
   type: string
   format: index
+label:
+  name: Label
+  entity: label
+  description: |
+    Tissue-type label, following a prescribed vocabulary.
+    Applies to binary masks and probabilistic/partial volume segmentations
+    that describe a single tissue type.
+
+    This entity is only applicable to derivative data.
+  type: string
+  format: label
+modality:
+  name: Corresponding Modality
+  entity: mod
+  description: |
+    The `mod-<label>` key/value pair corresponds to modality label for defacing
+    masks, for example, T1w, inplaneT1, referenced by a defacemask image.
+    For example, `sub-01_mod-T1w_defacemask.nii.gz`.
+  type: string
+  format: label
 mtransfer:
   name: Magnetization Transfer
   entity: mt
@@ -182,10 +134,9 @@ mtransfer:
     entity are `on` and `off`, for images acquired in presence and absence of an MT pulse,
     respectively.
   type: string
-  # on/off map to True/False in YAML so they must be placed in quotes.
   enum:
-    - "on"
-    - "off"
+  - 'on'
+  - 'off'
 part:
   name: Part
   entity: part
@@ -206,10 +157,33 @@ part:
     omitted.
   type: string
   enum:
-    - mag
-    - phase
-    - real
-    - imag
+  - mag
+  - phase
+  - real
+  - imag
+processing:
+  name: Processed (on device)
+  entity: proc
+  description: |
+    The proc label is analogous to rec for MR and denotes a variant of
+    a file that was a result of particular processing performed on the device.
+
+    This is useful for files produced in particular by Elekta's MaxFilter
+    (for example, sss, tsss, trans, quat or mc),
+    which some installations impose to be run on raw data because of active
+    shielding software corrections before the MEG data can actually be
+    exploited.
+  type: string
+  format: label
+reconstruction:
+  name: Reconstruction
+  entity: rec
+  description: |
+    The `rec-<label>` key/value can be used to distinguish
+    different reconstruction algorithms (for example ones using motion
+    correction).
+  type: string
+  format: label
 recording:
   name: Recording
   entity: recording
@@ -220,17 +194,64 @@ recording:
     For example: `_recording-contrast`, `_recording-saturation`.
   type: string
   format: label
-processing:
-  name: Processed (on device)
-  entity: proc
+resolution:
+  name: Resolution
+  entity: res
   description: |
-    The proc label is analogous to rec for MR and denotes a variant of a file
-    that was a result of particular processing performed on the device.
-    This is useful for files produced in particular by Elekta’s MaxFilter
-    (for example, sss, tsss, trans, quat or mc),
-    which some installations impose to be run on raw data because of active
-    shielding software corrections before the MEG data can actually be
-    exploited.
+    Resolution of regularly sampled N-dimensional data.
+    MUST have a corresponding `Resolution` metadata field to provide
+    interpretation.
+
+    This entity is only applicable to derivative data.
+  type: string
+  format: label
+run:
+  name: Run
+  entity: run
+  description: |
+    If several scans with the same acquisition parameters are acquired in the same session,
+    they MUST be indexed with the [`run-<index>`](../99-appendices/09-entities.md#run) entity:
+    `_run-1`, `_run-2`, `_run-3`, and so on (only nonnegative integers are allowed as
+    run labels).
+
+    If different entities apply,
+    such as a different session indicated by [`ses-<label>`](../99-appendices/09-entities.md#ses),
+    or different acquisition parameters indicated by
+    [`acq-<label>`](../99-appendices/09-entities.md#acq),
+    then `run` is not needed to distinguish the scans and MAY be omitted.
+  type: string
+  format: index
+sample:
+  name: Sample
+  entity: sample
+  description: |
+    A sample pertaining to a subject such as tissue, primary cell
+    or cell-free sample.
+    The `sample-<label>` key/value pair is used to distinguish between different
+    samples from the same subject.
+    The label MUST be unique per subject and is RECOMMENDED to be unique
+    throughout the dataset.
+  type: string
+  format: label
+session:
+  name: Session
+  entity: ses
+  description: |
+    A logical grouping of neuroimaging and behavioral data consistent across
+    subjects.
+    Session can (but doesn't have to) be synonymous to a visit in a
+    longitudinal study.
+    In general, subjects will stay in the scanner during one session.
+    However, for example, if a subject has to leave the scanner room and then
+    be re-positioned on the scanner bed, the set of MRI acquisitions will still
+    be considered as a session and match sessions acquired in other subjects.
+    Similarly, in situations where different data types are obtained over
+    several visits (for example fMRI on one day followed by DWI the day after)
+    those can be grouped in one session.
+    Defining multiple sessions is appropriate when several identical or similar
+    data acquisitions are planned and performed on all -or most- subjects,
+    often in the case of some intervention between sessions
+    (for example, training).
   type: string
   format: label
 space:
@@ -273,46 +294,30 @@ split:
     [Scans file](../03-modality-agnostic-files.md#scans-file).
   type: string
   format: index
-resolution:
-  name: Resolution
-  entity: res
-  description: |
-    Resolution of regularly sampled N-dimensional data.
-    MUST have a corresponding `Resolution` metadata field to provide
-    interpretation.
-
-    This entity is only applicable to derivative data.
-  type: string
-  format: label
-density:
-  name: Density
-  entity: den
+subject:
+  name: Subject
+  entity: sub
   description: |
-    Density of non-parametric surfaces.
-    MUST have a corresponding `Density` metadata field to provide
-    interpretation.
-
-    This entity is only applicable to derivative data.
+    A person or animal participating in the study.
   type: string
   format: label
-label:
-  name: Label
-  entity: label
+task:
+  name: Task
+  entity: task
   description: |
-    Tissue-type label, following a prescribed vocabulary.
-    Applies to binary masks and probabilistic/partial volume segmentations
-    that describe a single tissue type.
-
-    This entity is only applicable to derivative data.
+    Each task has a unique label that MUST only consist of letters and/or
+    numbers (other characters, including spaces and underscores, are not
+    allowed).
+    Those labels MUST be consistent across subjects and sessions.
   type: string
   format: label
-description:
-  name: Description
-  entity: desc
+tracer:
+  name: Tracer
+  entity: trc
   description: |
-    When necessary to distinguish two files that do not otherwise have a
-    distinguishing entity, the `_desc-<label>` keyword-value SHOULD be used.
-
-    This entity is only applicable to derivative data.
+    The `trc-<label>` key/value can be used to distinguish
+    sequences using different tracers.
+    The key `TracerName` MUST also be included in the associated JSON file,
+    although the label may be different.
   type: string
   format: label
diff --git a/src/schema/objects/metadata.yaml b/src/schema/objects/metadata.yaml
new file mode 100644
index 0000000000..a8e572a878
--- /dev/null
+++ b/src/schema/objects/metadata.yaml
@@ -0,0 +1,2790 @@
+---
+# This file defines valid BIDS metadata fields.
+# These definitions include the field names, their descriptions, and valid values.
+# This file **does not** define how and when metadata fields can be used with a given file.
+Acknowledgements:
+  name: Acknowledgements
+  description: |
+    Text acknowledging contributions of individuals or institutions beyond
+    those listed in Authors or Funding.
+  type: string
+AcquisitionDuration:
+  name: AcquisitionDuration
+  description: |
+    Duration (in seconds) of volume acquisition.
+    Corresponds to DICOM Tag 0018, 9073 `Acquisition Duration`.
+    This field is mutually exclusive with RepetitionTime.
+  type: number
+  exclusiveMinimum: 0
+  unit: s
+AcquisitionMode:
+  name: AcquisitionMode
+  description: |
+    Type of acquisition of the PET data (for example, `"list mode"`).
+  type: string
+AcquisitionVoxelSize:
+  name: AcquisitionVoxelSize
+  description: |
+    An array of numbers with a length of 3, in millimeters.
+    This parameter denotes the original acquisition voxel size,
+    excluding any inter-slice gaps and before any interpolation or resampling
+    within reconstruction or image processing.
+    Any point spread function effects, for example due to T2-blurring,
+    that would decrease the effective resolution are not considered here.
+  type: array
+  minItems: 3
+  maxItems: 3
+  items:
+    type: number
+    exclusiveMinimum: 0
+    unit: mm
+Anaesthesia:
+  name: Anaesthesia
+  description: |
+    Details of anaesthesia used, if any.
+  type: string
+AnalyticalApproach:
+  name: AnalyticalApproach
+  description: |
+    Methodology or methodologies used to analyse the `GeneticLevel`.
+    Values MUST be taken from the
+    [database of Genotypes and Phenotypes
+    (dbGaP)](https://www.ncbi.nlm.nih.gov/gap/advanced)
+    under /Study/Molecular Data Type (for example, SNP Genotypes (Array) or
+    Methylation (CpG).
+  anyOf:
+  - type: string
+  - type: array
+    items:
+      type: string
+AnatomicalLandmarkCoordinateSystem:
+  name: AnatomicalLandmarkCoordinateSystem
+  description: |
+    Defines the coordinate system for the anatomical landmarks.
+    See [Appendix VIII](/99-appendices/08-coordinate-systems.html)
+    for a list of restricted keywords for coordinate systems.
+    If `"Other"`, provide definition of the coordinate system in
+    `AnatomicalLandmarkCoordinateSystemDescription`.
+  anyOf:
+  - $ref: _MEGCoordSys
+  - $ref: _EEGCoordSys
+  - $ref: _StandardTemplateCoordSys
+  - $ref: _StandardTemplateDeprecatedCoordSys
+AnatomicalLandmarkCoordinateSystemDescription:
+  name: AnatomicalLandmarkCoordinateSystemDescription
+  description: |
+    Free-form text description of the coordinate system.
+    May also include a link to a documentation page or paper describing the
+    system in greater detail.
+  type: string
+AnatomicalLandmarkCoordinateUnits:
+  name: AnatomicalLandmarkCoordinateUnits
+  description: |
+    Units of the coordinates of `AnatomicalLandmarkCoordinateSystem`.
+    MUST be `"m"`, `"cm"`, or `"mm"`.
+  type: string
+  enum:
+  - m
+  - mm
+  - cm
+  - n/a
+AnatomicalLandmarkCoordinates:
+  name: AnatomicalLandmarkCoordinates
+  description: |
+    Key:value pairs of the labels and 3-D digitized locations of anatomical landmarks,
+    interpreted following the `AnatomicalLandmarkCoordinateSystem`
+    (for example, `{"NAS": [12.7,21.3,13.9], "LPA": [5.2,11.3,9.6],
+    "RPA": [20.2,11.3,9.1]}`.
+    Each array MUST contain three numeric values corresponding to x, y, and z
+    axis of the coordinate system in that exact order.
+  type: object
+  additionalProperties:
+    type: array
+    items:
+      type: number
+    minItems: 3
+    maxItems: 3
+AnatomicalLandmarkCoordinates_mri:
+  name: AnatomicalLandmarkCoordinates
+  description: |
+    Key:value pairs of any number of additional anatomical landmarks and their
+    coordinates in voxel units (where first voxel has index 0,0,0)
+    relative to the associated anatomical MRI
+    (for example, `{"AC": [127,119,149], "PC": [128,93,141],
+    "IH": [131,114,206]}`, or `{"NAS": [127,213,139], "LPA": [52,113,96],
+    "RPA": [202,113,91]}`).
+    Each array MUST contain three numeric values corresponding to x, y, and z
+    axis of the coordinate system in that exact order.
+  type: object
+  additionalProperties:
+    type: array
+    items:
+      type: number
+    minItems: 3
+    maxItems: 3
+ArterialSpinLabelingType:
+  name: ArterialSpinLabelingType
+  description: |
+    `"CASL"`, `"PCASL"`, `"PASL"`.
+  type: string
+  enum:
+  - CASL
+  - PCASL
+  - PASL
+AssociatedEmptyRoom:
+  name: AssociatedEmptyRoom
+  description: |
+    Relative path in BIDS folder structure to empty-room file associated with
+    the subject's MEG recording.
+    The path needs to use forward slashes instead of backward slashes
+    (for example,
+    "sub-emptyroom/ses-/meg/sub-emptyroom_ses-_task-noise_run-_meg.ds").
+  anyOf:
+  - type: array
+    items:
+      type: string
+      format: dataset_relative
+  - type: string
+    format: dataset_relative
+Atlas:
+  name: Atlas
+  description: |
+    Which atlas (if any) was used to generate the mask.
+  type: string
+AttenuationCorrection:
+  name: AttenuationCorrection
+  description: |
+    Short description of the attenuation correction method used.
+  type: string
+AttenuationCorrectionMethodReference:
+  name: AttenuationCorrectionMethodReference
+  description: |
+    Reference paper for the attenuation correction method used.
+  type: string
+Authors:
+  name: Authors
+  description: |
+    List of individuals who contributed to the creation/curation of the dataset.
+  type: array
+  items:
+    type: string
+B0FieldIdentifier:
+  name: B0FieldIdentifier
+  description: |
+    The presence of this key states that this particular 3D or 4D image MAY be
+    used for fieldmap estimation purposes.
+    The `B0FieldIdentifier` MUST be a unique string within one participant's tree,
+    shared only by the images meant to be used as inputs for the estimation of a
+    particular instance of the *B<sub>0</sub> field* estimation.
+    It is RECOMMENDED to derive this identifier from DICOM Tags, for example,
+    DICOM tag 0018, 1030 `Protocol Name`, or DICOM tag 0018, 0024 `Sequence Name`
+    when the former is not defined (for example, in GE devices.)
+  type: string
+  format: participant_relative
+B0FieldSource:
+  name: B0FieldSource
+  description: |
+    At least one existing `B0FieldIdentifier` defined by other images in the
+    participant's tree.
+    This field states the *B<sub>0</sub> field* estimation designated by the
+    `B0FieldIdentifier` that may be used to correct the dataset for distortions
+    caused by B<sub>0</sub> inhomogeneities.
+    `B0FieldSource` and `B0FieldIdentifier` are mutually exclusive.
+  anyOf:
+  - type: string
+    format: participant_relative
+  - type: array
+    items:
+      type: string
+      format: participant_relative
+BIDSVersion:
+  name: BIDSVersion
+  description: |
+    The version of the BIDS standard that was used.
+  type: string
+BackgroundSuppression:
+  name: BackgroundSuppression
+  description: |
+    Boolean indicating if background suppression is used.
+  type: boolean
+BackgroundSuppressionNumberPulses:
+  name: BackgroundSuppressionNumberPulses
+  description: |
+    The number of background suppression pulses used.
+    Note that this excludes any effect of background suppression pulses applied
+    before the labeling.
+  type: number
+  minimum: 0
+BackgroundSuppressionPulseTime:
+  name: BackgroundSuppressionPulseTime
+  description: |
+    Array of numbers containing timing, in seconds,
+    of the background suppression pulses with respect to the start of the
+    labeling.
+    In case of multi-PLD with different background suppression pulse times,
+    only the pulse time of the first PLD should be defined.
+  type: array
+  items:
+    type: number
+    minimum: 0
+    unit: s
+BasedOn:
+  name: BasedOn
+  description: |
+    List of files in a file collection to generate the map.
+    Fieldmaps are also listed, if involved in the processing.
+  anyOf:
+  - type: string
+    format: participant_relative
+  - type: array
+    items:
+      type: string
+      format: participant_relative
+BloodDensity:
+  name: BloodDensity
+  description: |
+    Measured blood density. Unit of blood density should be in `"g/mL"`.
+  type: number
+  unit: g/mL
+BodyPart:
+  name: BodyPart
+  description: |
+    Body part of the organ / body region scanned.
+    Corresponds to DICOM Tag 0018, 0015 `Body Part Examined`.
+  type: string
+BolusCutOffDelayTime:
+  name: BolusCutOffDelayTime
+  description: |
+    Duration between the end of the labeling and the start of the bolus cut-off
+    saturation pulse(s), in seconds.
+    This can be a number or array of numbers, of which the values must be
+    non-negative and monotonically increasing, depending on the number of bolus
+    cut-off saturation pulses.
+    For Q2TIPS, only the values for the first and last bolus cut-off saturation
+    pulses are provided.
+    Based on DICOM Tag 0018, 925F `ASL Bolus Cut-off Delay Time`.
+  anyOf:
+  - type: number
+    minimum: 0
+    unit: s
+  - type: array
+    items:
+      type: number
+      unit: s
+      minimum: 0
+BolusCutOffFlag:
+  name: BolusCutOffFlag
+  description: |
+    Boolean indicating if a bolus cut-off technique is used.
+    Corresponds to DICOM Tag 0018, 925C `ASL Bolus Cut-off Flag`.
+  type: boolean
+BolusCutOffTechnique:
+  name: BolusCutOffTechnique
+  description: |
+    Name of the technique used, for example `"Q2TIPS"`, `"QUIPSS"`, `"QUIPSSII"`.
+    Corresponds to DICOM Tag 0018, 925E `ASL Bolus Cut-off Technique`.
+  type: string
+BrainLocation:
+  name: BrainLocation
+  description: |
+    Refers to the location in space of the `TissueOrigin`.
+    Values may be an MNI coordinate,
+    a label taken from the
+    [Allen Brain Atlas](https://atlas.brain-map.org/atlas?atlas=265297125&plate=\
+    112360888&structure=4392&x=40348.15104166667&y=46928.75&zoom=-7&resolution=\
+    206.60&z=3),
+    or layer to refer to layer-specific gene expression,
+    which can also tie up with laminar fMRI.
+  type: string
+CASLType:
+  name: CASLType
+  description: |
+    Describes if a separate coil is used for labeling:
+    `"single-coil"` or `"double-coil"`.
+  type: string
+  enum:
+  - single-coil
+  - double-coil
+CapManufacturer:
+  name: CapManufacturer
+  description: |
+    Name of the cap manufacturer (for example, `"EasyCap"`).
+  type: string
+CapManufacturersModelName:
+  name: CapManufacturersModelName
+  description: |
+    Manufacturer's designation of the EEG cap model
+    (for example, `"actiCAP 64 Ch Standard-2"`).
+  type: string
+CellType:
+  name: CellType
+  description: |
+    Describes the type of cell analyzed.
+    Values SHOULD come from the
+    [cell ontology](http://obofoundry.org/ontology/cl.html).
+  type: string
+Code:
+  name: Code
+  description: |
+    [URI](/02-common-principles.html#uniform-resource-indicator)
+    of the code used to present the stimuli.
+    Persistent identifiers such as DOIs are preferred.
+    If multiple versions of code may be hosted at the same location,
+    revision-specific URIs are recommended.
+  type: string
+  format: uri
+CogAtlasID:
+  name: CogAtlasID
+  description: |
+    [URI](/02-common-principles.html#uniform-resource-indicator)
+    of the corresponding [Cognitive Atlas](https://www.cognitiveatlas.org/)
+    Task term.
+  type: string
+  format: uri
+CogPOID:
+  name: CogPOID
+  description: |
+    [URI](/02-common-principles.html#uniform-resource-indicator)
+    of the corresponding [CogPO](http://www.cogpo.org/) term.
+  type: string
+  format: uri
+CoilCombinationMethod:
+  name: CoilCombinationMethod
+  description: |
+    Almost all fMRI studies using phased-array coils use root-sum-of-squares
+    (rSOS) combination, but other methods exist.
+    The image reconstruction is changed by the coil combination method
+    (as for the matrix coil mode above),
+    so anything non-standard should be reported.
+  type: string
+Columns:
+  name: Columns
+  description: |
+    Names of columns in file.
+  type: array
+  items:
+    type: string
+ContinuousHeadLocalization:
+  name: ContinuousHeadLocalization
+  description: |
+    `true` or `false` value indicating whether continuous head localisation
+    was performed.
+  type: boolean
+ContrastBolusIngredient:
+  name: ContrastBolusIngredient
+  description: |
+    Active ingredient of agent.
+    Values MUST be one of: `"IODINE"`, `"GADOLINIUM"`, `"CARBON DIOXIDE"`,
+    `"BARIUM"`, `"XENON"`.
+    Corresponds to DICOM Tag 0018, 1048 `Contrast/Bolus Ingredient`.
+  type: string
+  enum:
+  - IODINE
+  - GADOLINIUM
+  - CARBON DIOXIDE
+  - BARIUM
+  - XENON
+DCOffsetCorrection:
+  name: DCOffsetCorrection
+  description: |
+    A description of the method (if any) used to correct for a DC offset.
+    If the method used was subtracting the mean value for each channel,
+    use "mean".
+  type: string
+DatasetDOI:
+  name: DatasetDOI
+  description: |
+    The Digital Object Identifier of the dataset (not the corresponding paper).
+    DOIs SHOULD be expressed as a valid
+    [URI](/02-common-principles.html#uniform-resource-indicator);
+    bare DOIs such as `10.0.2.3/dfjj.10` are
+    [DEPRECATED](/02-common-principles.html#definitions).
+  type: string
+  format: uri
+DatasetType:
+  name: DatasetType
+  description: |
+    The interpretation of the dataset.
+    MUST be one of `"raw"` or `"derivative"`.
+    For backwards compatibility, the default value is `"raw"`.
+  type: string
+  enum:
+  - raw
+  - derivative
+DecayCorrectionFactor:
+  name: DecayCorrectionFactor
+  description: |
+    Decay correction factor for each frame.
+  type: array
+  items:
+    type: number
+DelayAfterTrigger:
+  name: DelayAfterTrigger
+  description: |
+    Duration (in seconds) from trigger delivery to scan onset.
+    This delay is commonly caused by adjustments and loading times.
+    This specification is entirely independent of
+    `NumberOfVolumesDiscardedByScanner` or `NumberOfVolumesDiscardedByUser`,
+    as the delay precedes the acquisition.
+  type: number
+  unit: s
+DelayTime:
+  name: DelayTime
+  description: |
+    User specified time (in seconds) to delay the acquisition of data for the
+    following volume.
+    If the field is not present it is assumed to be set to zero.
+    Corresponds to Siemens CSA header field `lDelayTimeInTR`.
+    This field is REQUIRED for sparse sequences using the `RepetitionTime` field
+    that do not have the `SliceTiming` field set to allowed for accurate
+    calculation of "acquisition time".
+    This field is mutually exclusive with `VolumeTiming`.
+  type: number
+  unit: s
+Density:
+  name: Density
+  description: |
+    Specifies the interpretation of the density keyword.
+    If an object is used, then the keys should be values for the ``den`` entity
+    and values should be descriptions of those ``den`` values.
+  anyOf:
+  - type: string
+  - type: object
+    additionalProperties:
+      type: string
+Description:
+  name: Description
+  description: |
+    Free-form natural language description.
+  type: string
+DeviceSerialNumber:
+  name: DeviceSerialNumber
+  description: |
+    The serial number of the equipment that produced the measurements.
+    A pseudonym can also be used to prevent the equipment from being
+    identifiable, so long as each pseudonym is unique within the dataset.
+  type: string
+DewarPosition:
+  name: DewarPosition
+  description: |
+    Position of the dewar during the MEG scan:
+    `"upright"`, `"supine"` or `"degrees"` of angle from vertical:
+    for example on CTF systems, `"upright=15°, supine=90°"`.
+  type: string
+DigitizedHeadPoints:
+  name: DigitizedHeadPoints
+  description: |
+    `true` or `false` value indicating whether head points outlining the
+    scalp/face surface are contained within this recording.
+  type: boolean
+DigitizedHeadPointsCoordinateSystem:
+  name: DigitizedHeadPointsCoordinateSystem
+  description: |
+    Defines the coordinate system for the digitized head points.
+    See
+    [Appendix VIII](/99-appendices/08-coordinate-systems.html)
+    for a list of restricted keywords for coordinate systems.
+    If `"Other"`, provide definition of the coordinate system in
+    `DigitizedHeadPointsCoordinateSystemDescription`.
+  anyOf:
+  - $ref: _MEGCoordSys
+  - $ref: _EEGCoordSys
+  - $ref: _StandardTemplateCoordSys
+  - $ref: _StandardTemplateDeprecatedCoordSys
+DigitizedHeadPointsCoordinateSystemDescription:
+  name: DigitizedHeadPointsCoordinateSystemDescription
+  description: |
+    Free-form text description of the coordinate system.
+    May also include a link to a documentation page or paper describing the
+    system in greater detail.
+  type: string
+DigitizedHeadPointsCoordinateUnits:
+  name: DigitizedHeadPointsCoordinateUnits
+  description: |
+    Units of the coordinates of `DigitizedHeadPointsCoordinateSystem`.
+    MUST be `"m"`, `"cm"`, or `"mm"`.
+  type: string
+  enum:
+  - m
+  - mm
+  - cm
+  - n/a
+DigitizedLandmarks:
+  name: DigitizedLandmarks
+  description: |
+    `true` or `false` value indicating whether anatomical landmark points
+    (fiducials) are contained within this recording.
+  type: boolean
+DispersionConstant:
+  name: DispersionConstant
+  description: |
+    External dispersion time constant resulting from tubing in default unit
+    seconds.
+  type: number
+  unit: s
+DispersionCorrected:
+  name: DispersionCorrected
+  description: |
+    Boolean flag specifying whether the blood data have been dispersion-corrected.
+    NOTE: not customary for manual samples, and hence should be set to `false`.
+  type: boolean
+DoseCalibrationFactor:
+  name: DoseCalibrationFactor
+  description: |
+    Multiplication factor used to transform raw data (in counts/sec) to meaningful unit (Bq/ml).
+    Corresponds to DICOM Tag 0054, 1322 `Dose Calibration Factor`.
+  type: number
+DwellTime:
+  name: DwellTime
+  description: |
+    Actual dwell time (in seconds) of the receiver per point in the readout
+    direction, including any oversampling.
+    For Siemens, this corresponds to DICOM field 0019, 1018 (in ns).
+    This value is necessary for the optional readout distortion correction of
+    anatomicals in the HCP Pipelines.
+    It also usefully provides a handle on the readout bandwidth,
+    which isn't captured in the other metadata tags.
+    Not to be confused with `EffectiveEchoSpacing`, and the frequent mislabeling
+    of echo spacing (which is spacing in the phase encoding direction) as
+    "dwell time" (which is spacing in the readout direction).
+  type: number
+  unit: s
+ECGChannelCount:
+  name: ECGChannelCount
+  description: |
+    Number of ECG channels.
+  type: integer
+  minimum: 0
+ECOGChannelCount:
+  name: ECOGChannelCount
+  description: |
+    Number of ECoG channels.
+  type: integer
+  minimum: 0
+EEGChannelCount:
+  name: EEGChannelCount
+  description: |
+    Number of EEG channels recorded simultaneously (for example, `21`).
+  type: integer
+  minimum: 0
+EEGCoordinateSystem:
+  name: EEGCoordinateSystem
+  description: |
+    Defines the coordinate system for the EEG sensors.
+
+    See
+    [Appendix VIII](/99-appendices/08-coordinate-systems.html)
+    for a list of restricted keywords for coordinate systems.
+    If `"Other"`, provide definition of the coordinate system in
+    `EEGCoordinateSystemDescription`.
+  anyOf:
+  - $ref: _MEGCoordSys
+  - $ref: _EEGCoordSys
+  - $ref: _StandardTemplateCoordSys
+  - $ref: _StandardTemplateDeprecatedCoordSys
+EEGCoordinateSystemDescription:
+  name: EEGCoordinateSystemDescription
+  description: |
+    Free-form text description of the coordinate system.
+    May also include a link to a documentation page or paper describing the
+    system in greater detail.
+  type: string
+EEGCoordinateUnits:
+  name: EEGCoordinateUnits
+  description: |
+    Units of the coordinates of `EEGCoordinateSystem`.
+    MUST be `"m"`, `"cm"`, or `"mm"`.
+  type: string
+  enum:
+  - m
+  - mm
+  - cm
+  - n/a
+EEGGround:
+  name: EEGGround
+  description: |
+    Description of the location of the ground electrode
+    (for example, `"placed on right mastoid (M2)"`).
+  type: string
+EEGPlacementScheme:
+  name: EEGPlacementScheme
+  description: |
+    Placement scheme of EEG electrodes.
+    Either the name of a standardized placement system (for example, `"10-20"`)
+    or a list of standardized electrode names (for example, `["Cz", "Pz"]`).
+  type: string
+EEGReference:
+  name: EEGReference
+  description: |
+    General description of the reference scheme used and (when applicable) of
+    location of the reference electrode in the raw recordings
+    (for example, `"left mastoid"`, `"Cz"`, `"CMS"`).
+    If different channels have a different reference,
+    this field should have a general description and the channel specific
+    reference should be defined in the `channels.tsv` file.
+  type: string
+EMGChannelCount:
+  name: EMGChannelCount
+  description: |
+    Number of EMG channels.
+  type: integer
+  minimum: 0
+EOGChannelCount:
+  name: EOGChannelCount
+  description: |
+    Number of EOG channels.
+  type: integer
+  minimum: 0
+EchoTime:
+  name: EchoTime
+  description: |
+    The echo time (TE) for the acquisition, specified in seconds.
+    Corresponds to DICOM Tag 0018, 0081 `Echo Time`
+    (please note that the DICOM term is in milliseconds not seconds).
+    The data type number may apply to files from any MRI modality concerned with
+    a single value for this field, or to the files in a
+    [file collection](/99-appendices/10-file-collections.html)
+    where the value of this field is iterated using the
+    [echo entity](/99-appendices/09-entities.html#echo).
+    The data type array provides a value for each volume in a 4D dataset and
+    should only be used when the volume timing is critical for interpretation
+    of the data, such as in
+    [ASL](/04-modality-specific-files/01-magnetic-resonance-imaging-data.html#\
+    arterial-spin-labeling-perfusion-data)
+    or variable echo time fMRI sequences.
+  anyOf:
+  - type: number
+    unit: s
+    exclusiveMinimum: 0
+  - type: array
+    items:
+      type: number
+      unit: s
+      exclusiveMinimum: 0
+EchoTime1:
+  name: EchoTime1
+  description: |
+    The time (in seconds) when the first (shorter) echo occurs.
+  type: number
+  unit: s
+  exclusiveMinimum: 0
+EchoTime2:
+  name: EchoTime2
+  description: |
+    The time (in seconds) when the second (longer) echo occurs.
+  type: number
+  unit: s
+  exclusiveMinimum: 0
+EchoTime_fmap:
+  name: EchoTime
+  description: |
+    The time (in seconds) when the echo corresponding to this map was acquired.
+  type: number
+  unit: s
+  exclusiveMinimum: 0
+EffectiveEchoSpacing:
+  name: EffectiveEchoSpacing
+  description: |
+    The "effective" sampling interval, specified in seconds,
+    between lines in the phase-encoding direction,
+    defined based on the size of the reconstructed image in the phase direction.
+    It is frequently, but incorrectly, referred to as "dwell time"
+    (see `DwellTime` parameter below for actual dwell time).
+    It is required for unwarping distortions using field maps.
+    Note that beyond just in-plane acceleration,
+    a variety of other manipulations to the phase encoding need to be accounted
+    for properly, including partial fourier, phase oversampling,
+    phase resolution, phase field-of-view and interpolation.
+  type: number
+  exclusiveMinimum: 0
+  unit: s
+ElectricalStimulation:
+  name: ElectricalStimulation
+  description: |
+    Boolean field to specify if electrical stimulation was done during the
+    recording (options are `true` or `false`). Parameters for event-like
+    stimulation should be specified in the events.tsv file.
+  type: boolean
+ElectricalStimulationParameters:
+  name: ElectricalStimulationParameters
+  description: |
+    Free form description of stimulation parameters, such as frequency or shape.
+    Specific onsets can be specified in the events.tsv file.
+    Specific shapes can be described here in freeform text.
+  type: string
+ElectrodeManufacturer:
+  name: ElectrodeManufacturer
+  description: |
+    Can be used if all electrodes are of the same manufacturer
+    (for example, `"AD-TECH"`, `"DIXI"`).
+    If electrodes of different manufacturers are used,
+    please use the corresponding table in the `_electrodes.tsv` file.
+  type: string
+ElectrodeManufacturersModelName:
+  name: ElectrodeManufacturersModelName
+  description: |
+    If different electrode types are used,
+    please use the corresponding table in the `_electrodes.tsv` file.
+  type: string
+EpochLength:
+  name: EpochLength
+  description: |
+    Duration of individual epochs in seconds (for example, `1`)
+    in case of epoched data.
+    If recording was continuous or discontinuous, leave out the field.
+  type: number
+  minimum: 0
+EstimationAlgorithm:
+  name: EstimationAlgorithm
+  description: |
+    Type of algorithm used to perform fitting
+    (for example, linear, non-linear, LM and such).
+  type: string
+EstimationReference:
+  name: EstimationReference
+  description: |
+    Reference to the study/studies on which the implementation is based.
+  type: string
+EthicsApprovals:
+  name: EthicsApprovals
+  description: |
+    List of ethics committee approvals of the research protocols and/or
+    protocol identifiers.
+  type: array
+  items:
+    type: string
+FiducialsCoordinateSystem:
+  name: FiducialsCoordinateSystem
+  description: |
+    Defines the coordinate system for the fiducials.
+    Preferably the same as the `EEGCoordinateSystem`.
+    See
+    [Appendix VIII](/99-appendices/08-coordinate-systems.html)
+    for a list of restricted keywords for coordinate systems.
+    If `"Other"`, provide definition of the coordinate system in
+    `FiducialsCoordinateSystemDescription`.
+  anyOf:
+  - $ref: _MEGCoordSys
+  - $ref: _EEGCoordSys
+  - $ref: _StandardTemplateCoordSys
+  - $ref: _StandardTemplateDeprecatedCoordSys
+FiducialsCoordinateSystemDescription:
+  name: FiducialsCoordinateSystemDescription
+  description: |
+    Free-form text description of the coordinate system.
+    May also include a link to a documentation page or paper describing the
+    system in greater detail.
+  type: string
+FiducialsCoordinateUnits:
+  name: FiducialsCoordinateUnits
+  description: |
+    Units in which the coordinates that are  listed in the field
+    `FiducialsCoordinateSystem` are represented.
+    MUST be `"m"`, `"cm"`, or `"mm"`.
+  type: string
+  enum:
+  - m
+  - mm
+  - cm
+  - n/a
+FiducialsCoordinates:
+  name: FiducialsCoordinates
+  description: |
+    Key:value pairs of the labels and 3-D digitized position of anatomical
+    landmarks, interpreted following the `FiducialsCoordinateSystem`
+    (for example, `{"NAS": [12.7,21.3,13.9], "LPA": [5.2,11.3,9.6],
+    "RPA": [20.2,11.3,9.1]}`).
+    Each array MUST contain three numeric values corresponding to x, y, and z
+    axis of the coordinate system in that exact order.
+  type: object
+  additionalProperties:
+    type: array
+    items:
+      type: number
+    minItems: 3
+    maxItems: 3
+FiducialsDescription:
+  name: FiducialsDescription
+  description: |
+    Free-form text description of how the fiducials such as vitamin-E capsules
+    were placed relative to anatomical landmarks,
+    and how the position of the fiducials were measured
+    (for example, both with Polhemus and with T1w MRI).
+  type: string
+FlipAngle:
+  name: FlipAngle
+  description: |
+    Flip angle (FA) for the acquisition, specified in degrees.
+    Corresponds to: DICOM Tag 0018, 1314 `Flip Angle`.
+    The data type number may apply to files from any MRI modality concerned with
+    a single value for this field, or to the files in a
+    [file collection](/99-appendices/10-file-collections.html)
+    where the value of this field is iterated using the
+    [flip entity](/99-appendices/09-entities.html#flip).
+    The data type array provides a value for each volume in a 4D dataset and
+    should only be used when the volume timing is critical for interpretation of
+    the data, such as in
+    [ASL](/04-modality-specific-files/01-magnetic-resonance-imaging-data.html#\
+    arterial-spin-labeling-perfusion-data)
+    or variable flip angle fMRI sequences.
+  anyOf:
+  - type: number
+    unit: degree
+    exclusiveMinimum: 0
+    maximum: 360
+  - type: array
+    items:
+      type: number
+      unit: degree
+      exclusiveMinimum: 0
+      maximum: 360
+FrameDuration:
+  name: FrameDuration
+  description: |
+    Time duration of each frame in default unit seconds.
+    This corresponds to DICOM Tag 0018, 1242 `Actual Frame Duration` converted
+    to seconds.
+  type: array
+  items:
+    type: number
+  unit: s
+FrameTimesStart:
+  name: FrameTimesStart
+  description: |
+    Start times for all frames relative to `TimeZero` in default unit seconds.
+  type: array
+  items:
+    type: number
+  unit: s
+Funding:
+  name: Funding
+  description: |
+    List of sources of funding (grant numbers).
+  type: array
+  items:
+    type: string
+GeneratedBy:
+  name: GeneratedBy
+  description: |
+    Used to specify provenance of the derived dataset.
+    See table below for contents of each object.
+  type: array
+  minItems: 1
+  items:
+    type: object
+    properties:
+      Name:
+        type: string
+      Version:
+        type: string
+      Description:
+        type: string
+      CodeURL:
+        type: string
+        format: uri
+      Container:
+        type: object
+        properties:
+          Type:
+            type: string
+          Tag:
+            type: string
+          URI:
+            type: string
+            format: uri
+GeneticLevel:
+  name: GeneticLevel
+  description: |
+    Describes the level of analysis.
+    Values MUST be one of `"Genetic"`, `"Genomic"`, `"Epigenomic"`,
+    `"Transcriptomic"`, `"Metabolomic"`, or `"Proteomic"`.
+  anyOf:
+  - $ref: _GeneticLevelEnum
+  - type: array
+    items:
+      $ref: _GeneticLevelEnum
+Genetics.Database:
+  name: Genetics.Database
+  description: |
+    [URI](/02-common-principles.html#uniform-resource-indicator)
+    of database where the dataset is hosted.
+  type: string
+  format: uri
+Genetics.Dataset:
+  name: Genetics.Dataset
+  description: |
+    [URI](/02-common-principles.html#uniform-resource-indicator)
+    where data can be retrieved.
+  type: string
+  format: uri
+Genetics.Descriptors:
+  name: Genetics.Descriptors
+  description: |
+    List of relevant descriptors (for example, journal articles) for dataset
+    using a valid
+    [URI](/02-common-principles.html#uniform-resource-indicator)
+    when possible.
+  anyOf:
+  - type: string
+  - type: array
+    items:
+      type: string
+Genetics:
+  name: Genetics
+  description: |
+    An object containing information about the genetics descriptor.
+  type: object
+  properties:
+    Database:
+      $ref: Genetics.Database
+    Dataset:
+      $ref: Genetics.Dataset
+    Descriptors:
+      $ref: Genetics.Descriptors
+GradientSetType:
+  name: GradientSetType
+  description: |
+    It should be possible to infer the gradient coil from the scanner model.
+    If not, for example because of a custom upgrade or use of a gradient
+    insert set, then the specifications of the actual gradient coil should be
+    reported independently.
+  type: string
+HED:
+  name: HED
+  description: |
+    Hierarchical Event Descriptor (HED) information,
+    see: [Appendix III](/99-appendices/03-hed.html) for details.
+  anyOf:
+  - type: string
+  - type: object
+    additionalProperties:
+      type: string
+HEDVersion:
+  name: HEDVersion
+  description: |
+    If HED tags are used:
+    The version of the HED schema used to validate HED tags for study.
+  type: string
+Haematocrit:
+  name: Haematocrit
+  description: |
+    Measured haematocrit, meaning the volume of erythrocytes divided by the
+    volume of whole blood.
+  type: number
+HardcopyDeviceSoftwareVersion:
+  name: HardcopyDeviceSoftwareVersion
+  description: |
+    Manufacturer's designation of the software of the device that created this
+    Hardcopy Image (the printer).
+    Corresponds to DICOM Tag 0018, 101A `Hardcopy Device Software Version`.
+  type: string
+HardwareFilters:
+  name: HardwareFilters
+  description: |
+    Object of temporal hardware filters applied, or "n/a" if the data is not
+    available. Each key:value pair in the JSON object is a name of the filter and
+    an object in which its parameters are defined as key:value pairs.
+    For example, `{"Highpass RC filter": {"Half amplitude cutoff (Hz)":
+    0.0159, "Roll-off": "6dB/Octave"}}`.
+  anyOf:
+  - type: object
+    additionalProperties:
+      type: object
+  - type: string
+    enum:
+    - n/a
+HeadCircumference:
+  name: HeadCircumference
+  description: |
+    Circumference of the participant's head, expressed in cm (for example, `58`).
+  type: number
+  exclusiveMinimum: 0
+  unit: cm
+HeadCoilCoordinateSystem:
+  name: HeadCoilCoordinateSystem
+  description: |
+    Defines the coordinate system for the head coils.
+    See
+    [Appendix VIII](/99-appendices/08-coordinate-systems.html)
+    for a list of restricted keywords for coordinate systems.
+    If `"Other"`, provide definition of the coordinate system in
+    `HeadCoilCoordinateSystemDescription`.
+  anyOf:
+  - $ref: _MEGCoordSys
+  - $ref: _EEGCoordSys
+  - $ref: _StandardTemplateCoordSys
+  - $ref: _StandardTemplateDeprecatedCoordSys
+HeadCoilCoordinateSystemDescription:
+  name: HeadCoilCoordinateSystemDescription
+  description: |
+    Free-form text description of the coordinate system.
+    May also include a link to a documentation page or paper describing the system in greater detail.
+  type: string
+HeadCoilCoordinateUnits:
+  name: HeadCoilCoordinateUnits
+  description: |
+    Units of the coordinates of `HeadCoilCoordinateSystem`.
+    MUST be `"m"`, `"cm"`, or `"mm"`.
+  type: string
+  enum:
+  - m
+  - mm
+  - cm
+  - n/a
+HeadCoilCoordinates:
+  name: HeadCoilCoordinates
+  description: |
+    Key:value pairs describing head localization coil labels and their
+    coordinates, interpreted following the `HeadCoilCoordinateSystem`
+    (for example, `{"NAS": [12.7,21.3,13.9], "LPA": [5.2,11.3,9.6],
+    "RPA": [20.2,11.3,9.1]}`).
+    Note that coils are not always placed at locations that have a known
+    anatomical name (for example, for Elekta, Yokogawa systems); in that case
+    generic labels can be used
+    (for example, `{"coil1": [12.2,21.3,12.3], "coil2": [6.7,12.3,8.6],
+    "coil3": [21.9,11.0,8.1]}`).
+    Each array MUST contain three numeric values corresponding to x, y, and z
+    axis of the coordinate system in that exact order.
+  type: object
+  additionalProperties:
+    type: array
+    items:
+      type: number
+    minItems: 3
+    maxItems: 3
+HeadCoilFrequency:
+  name: HeadCoilFrequency
+  description: |
+    List of frequencies (in Hz) used by the head localisation coils
+    ('HLC' in CTF systems, 'HPI' in Elekta, 'COH' in BTi/4D)
+    that track the subject's head position in the MEG helmet
+    (for example, `[293, 307, 314, 321]`).
+  anyOf:
+  - type: number
+    unit: Hz
+  - type: array
+    items:
+      type: number
+      unit: Hz
+HowToAcknowledge:
+  name: HowToAcknowledge
+  description: |
+    Text containing instructions on how researchers using this dataset should
+    acknowledge the original authors.
+    This field can also be used to define a publication that should be cited in
+    publications that use the dataset.
+  type: string
+ImageDecayCorrected:
+  name: ImageDecayCorrected
+  description: |
+    Boolean flag specifying whether the image data have been decay-corrected.
+  type: boolean
+ImageDecayCorrectionTime:
+  name: ImageDecayCorrectionTime
+  description: |
+    Point in time from which the decay correction was applied with respect to
+    TimeZero in the default unit seconds.
+  type: number
+  unit: s
+InfusionRadioactivity:
+  name: InfusionRadioactivity
+  description: |
+    Amount of radioactivity infused into the patient.
+    This value must be less than or equal to the total injected radioactivity
+    (`InjectedRadioactivity`).
+    Units should be the same as `InjectedRadioactivityUnits`.
+  type: number
+InfusionSpeed:
+  name: InfusionSpeed
+  description: |
+    If given, infusion speed.
+  type: number
+InfusionSpeedUnits:
+  name: InfusionSpeedUnits
+  description: |
+    Unit of infusion speed (for example, `"mL/s"`).
+  type: string
+  format: unit
+InfusionStart:
+  name: InfusionStart
+  description: |
+    Time of start of infusion with respect to `TimeZero` in the default unit
+    seconds.
+  type: number
+  unit: s
+InjectedMass:
+  name: InjectedMass
+  description: |
+    Total mass of radiolabeled compound injected into subject (for example, 10).
+    This can be derived as the ratio of the `InjectedRadioactivity` and
+    `MolarRadioactivity`.
+    **For those tracers in which injected mass is not available (for example FDG)
+    can be set to `"n/a"`)**.
+  anyOf:
+  - type: number
+  - type: string
+    enum:
+    - n/a
+InjectedMassPerWeight:
+  name: InjectedMassPerWeight
+  description: |
+    Injected mass per kilogram bodyweight.
+  type: number
+InjectedMassPerWeightUnits:
+  name: InjectedMassPerWeightUnits
+  description: |
+    Unit format of the injected mass per kilogram bodyweight
+    (for example, `"ug/kg"`).
+  type: string
+  format: unit
+InjectedMassUnits:
+  name: InjectedMassUnits
+  description: |
+    Unit format of the mass of compound injected (for example, `"ug"` or
+    `"umol"`).
+    **Note this is not required for an FDG acquisition, since it is not available,
+    and SHOULD be set to `"n/a"`**.
+  anyOf:
+  - type: string
+    format: unit
+  - type: string
+    enum:
+    - n/a
+InjectedRadioactivity:
+  name: InjectedRadioactivity
+  description: |
+    Total amount of radioactivity injected into the patient (for example, 400).
+    For bolus-infusion experiments, this value should be the sum of all injected
+    radioactivity originating from both bolus and infusion.
+    Corresponds to DICOM Tag 0018, 1074 `Radionuclide Total Dose`.
+  type: number
+InjectedRadioactivityUnits:
+  name: InjectedRadioactivityUnits
+  description: |
+    Unit format of the specified injected radioactivity (for example, `"MBq"`).
+  type: string
+  format: unit
+InjectedVolume:
+  name: InjectedVolume
+  description: |
+    Injected volume of the radiotracer in the unit `"mL"`.
+  type: number
+  unit: mL
+InjectionEnd:
+  name: InjectionEnd
+  description: |
+    Time of end of injection with respect to `TimeZero` in the default unit
+    seconds.
+  type: number
+  unit: s
+InjectionStart:
+  name: InjectionStart
+  description: |
+    Time of start of injection with respect to `TimeZero` in the default unit
+    seconds.
+    This corresponds to DICOM Tag 0018, 1042 `Contrast/Bolus Start Time`
+    converted to seconds relative to `TimeZero`.
+  type: number
+  unit: s
+InstitutionAddress:
+  name: InstitutionAddress
+  description: |
+    The address of the institution in charge of the equipment that produced the
+    measurements.
+  type: string
+InstitutionName:
+  name: InstitutionName
+  description: |
+    The name of the institution in charge of the equipment that produced the
+    measurements.
+  type: string
+InstitutionalDepartmentName:
+  name: InstitutionalDepartmentName
+  description: |
+    The department in the institution in charge of the equipment that produced
+    the measurements.
+  type: string
+Instructions:
+  name: Instructions
+  description: |
+    Text of the instructions given to participants before the recording.
+  type: string
+IntendedFor:
+  name: IntendedFor
+  description: |
+    The paths to files for which the associated file is intended to be used.
+    Contains one or more filenames with paths relative to the participant
+    subfolder.
+    Paths need to use forward slashes instead of backward slashes,
+    regardless of operating system.
+  anyOf:
+  - type: string
+    format: participant_relative
+  - type: array
+    items:
+      type: string
+      format: participant_relative
+InversionTime:
+  name: InversionTime
+  description: |
+    The inversion time (TI) for the acquisition, specified in seconds.
+    Inversion time is the time after the middle of inverting RF pulse to middle
+    of excitation pulse to detect the amount of longitudinal magnetization.
+    Corresponds to DICOM Tag 0018, 0082 `Inversion Time`
+    (please note that the DICOM term is in milliseconds not seconds).
+  type: number
+  unit: s
+  exclusiveMinimum: 0
+LabelingDistance:
+  name: LabelingDistance
+  description: |
+    Distance from the center of the imaging slab to the center of the labeling
+    plane (`(P)CASL`) or the leading edge of the labeling slab (`PASL`),
+    in millimeters.
+    If the labeling is performed inferior to the isocenter,
+    this number should be negative.
+    Based on DICOM macro C.8.13.5.14.
+  type: number
+  unit: mm
+LabelingDuration:
+  name: LabelingDuration
+  description: |
+    Total duration of the labeling pulse train, in seconds,
+    corresponding to the temporal width of the labeling bolus for
+    `"PCASL"` or `"CASL"`.
+    In case all control-label volumes (or deltam or CBF) have the same
+    `LabelingDuration`, a scalar must be specified.
+    In case the control-label volumes (or deltam or cbf) have a different
+    `LabelingDuration`, an array of numbers must be specified,
+    for which any `m0scan` in the timeseries has a `LabelingDuration` of zero.
+    In case an array of numbers is provided,
+    its length should be equal to the number of volumes specified in
+    `*_aslcontext.tsv`.
+    Corresponds to DICOM Tag 0018, 9258 `ASL Pulse Train Duration`.
+  anyOf:
+  - type: number
+    minimum: 0
+    unit: s
+  - type: array
+    items:
+      type: number
+      unit: s
+      minimum: 0
+LabelingEfficiency:
+  name: LabelingEfficiency
+  description: |
+    Labeling efficiency, specified as a number between zero and one,
+    only if obtained externally (for example phase-contrast based).
+  type: number
+  exclusiveMinimum: 0
+LabelingLocationDescription:
+  name: LabelingLocationDescription
+  description: |
+    Description of the location of the labeling plane (`"CASL"` or `"PCASL"`) or
+    the labeling slab (`"PASL"`) that cannot be captured by fields
+    `LabelingOrientation` or `LabelingDistance`.
+    May include a link to an anonymized screenshot of the planning of the
+    labeling slab/plane with respect to the imaging slab or slices
+    `*_asllabeling.jpg`.
+    Based on DICOM macro C.8.13.5.14.
+  type: string
+LabelingOrientation:
+  name: LabelingOrientation
+  description: |
+    Orientation of the labeling plane (`(P)CASL`) or slab (`PASL`).
+    The direction cosines of a normal vector perpendicular to the ASL labeling
+    slab or plane with respect to the patient.
+    Corresponds to DICOM Tag 0018, 9255 `ASL Slab Orientation`.
+  type: array
+  items:
+    type: number
+LabelingPulseAverageB1:
+  name: LabelingPulseAverageB1
+  description: |
+    The average B1-field strength of the RF labeling pulses, in microteslas.
+    As an alternative, `LabelingPulseFlipAngle` can be provided.
+  type: number
+  exclusiveMinimum: 0
+  unit: uT
+LabelingPulseAverageGradient:
+  name: LabelingPulseAverageGradient
+  description: |
+    The average labeling gradient, in milliteslas per meter.
+  type: number
+  exclusiveMinimum: 0
+  unit: mT/m
+LabelingPulseDuration:
+  name: LabelingPulseDuration
+  description: |
+    Duration of the individual labeling pulses, in milliseconds.
+  type: number
+  exclusiveMinimum: 0
+  unit: ms
+LabelingPulseFlipAngle:
+  name: LabelingPulseFlipAngle
+  description: |
+    The flip angle of a single labeling pulse, in degrees,
+    which can be given as an alternative to `LabelingPulseAverageB1`.
+  type: number
+  exclusiveMinimum: 0
+  maximum: 360
+  unit: degree
+LabelingPulseInterval:
+  name: LabelingPulseInterval
+  description: |
+    Delay between the peaks of the individual labeling pulses, in milliseconds.
+  type: number
+  exclusiveMinimum: 0
+  unit: ms
+LabelingPulseMaximumGradient:
+  name: LabelingPulseMaximumGradient
+  description: |
+    The maximum amplitude of the gradient switched on during the application of
+    the labeling RF pulse(s), in milliteslas per meter.
+  type: number
+  exclusiveMinimum: 0
+  unit: mT/m
+LabelingSlabThickness:
+  name: LabelingSlabThickness
+  description: |
+    Thickness of the labeling slab in millimeters.
+    For non-selective FAIR a zero is entered.
+    Corresponds to DICOM Tag 0018, 9254 `ASL Slab Thickness`.
+  type: number
+  exclusiveMinimum: 0
+  unit: mm
+Levels:
+  name: Levels
+  description: |
+    For categorical variables: An object of possible values (keys) and their
+    descriptions (values).
+  type: object
+  additionalProperties:
+    type: string
+License:
+  name: License
+  description: |
+    The license for the dataset.
+    The use of license name abbreviations is RECOMMENDED for specifying a license
+    (see [Appendix II](/99-appendices/02-licenses.html)).
+    The corresponding full license text MAY be specified in an additional
+    `LICENSE` file.
+  type: string
+LongName:
+  name: LongName
+  description: |
+    Long (unabbreviated) name of the column.
+  type: string
+LookLocker:
+  name: LookLocker
+  description: |
+    Boolean indicating if a Look-Locker readout is used.
+  type: boolean
+M0Estimate:
+  name: M0Estimate
+  description: |
+    A single numerical whole-brain M0 value (referring to the M0 of blood),
+    only if obtained externally
+    (for example retrieved from CSF in a separate measurement).
+  type: number
+  exclusiveMinimum: 0
+M0Type:
+  name: M0Type
+  description: |
+    Describes the presence of M0 information, as either:
+    `"Separate"` when a separate `*_m0scan.nii[.gz]` is present,
+    `"Included"` when an m0scan volume is contained within the current
+    `*_asl.nii[.gz]`,
+    `"Estimate"` when a single whole-brain M0 value is provided, or
+    `"Absent"` when no specific M0 information is present.
+  type: string
+  enum:
+  - Separate
+  - Included
+  - Estimate
+  - Absent
+MEGChannelCount:
+  name: MEGChannelCount
+  description: |
+    Number of MEG channels (for example, 275).
+  type: integer
+  minimum: 0
+MEGCoordinateSystem:
+  name: MEGCoordinateSystem
+  description: |
+    Defines the coordinate system for the MEG sensors.
+    See [Appendix VIII](/99-appendices/08-coordinate-systems.html)
+    for a list of restricted keywords for coordinate systems.
+    If `"Other"`, provide definition of the coordinate system in
+    `MEGCoordinateSystemDescription`.
+  anyOf:
+  - $ref: _MEGCoordSys
+  - $ref: _EEGCoordSys
+  - $ref: _StandardTemplateCoordSys
+  - $ref: _StandardTemplateDeprecatedCoordSys
+MEGCoordinateSystemDescription:
+  name: MEGCoordinateSystemDescription
+  description: |
+    Free-form text description of the coordinate system.
+    May also include a link to a documentation page or paper describing the
+    system in greater detail.
+  type: string
+MEGCoordinateUnits:
+  name: MEGCoordinateUnits
+  description: |
+    Units of the coordinates of `MEGCoordinateSystem`.
+    MUST be `"m"`, `"cm"`, or `"mm"`.
+  type: string
+  enum:
+  - m
+  - mm
+  - cm
+  - n/a
+MEGREFChannelCount:
+  name: MEGREFChannelCount
+  description: |
+    Number of MEG reference channels (for example, 23).
+    For systems without such channels (for example, Neuromag Vectorview),
+    `MEGREFChannelCount` should be set to `0`.
+  type: integer
+  minimum: 0
+MRAcquisitionType:
+  name: MRAcquisitionType
+  description: |
+    Possible values: `"2D"` or `"3D"`.
+    Type of sequence readout.
+    Corresponds to DICOM Tag 0018, 0023 `MR Acquisition Type`.
+  type: string
+  enum:
+  - 2D
+  - 3D
+MRTransmitCoilSequence:
+  name: MRTransmitCoilSequence
+  description: |
+    This is a relevant field if a non-standard transmit coil is used.
+    Corresponds to DICOM Tag 0018, 9049 `MR Transmit Coil Sequence`.
+  type: string
+MTNumberOfPulses:
+  name: MTNumberOfPulses
+  description: |
+    The number of magnetization transfer RF pulses applied before the readout.
+  type: number
+MTOffsetFrequency:
+  name: MTOffsetFrequency
+  description: |
+    The frequency offset of the magnetization transfer pulse with respect to the
+    central H1 Larmor frequency in Hertz (Hz).
+  type: number
+  unit: Hz
+MTPulseBandwidth:
+  name: MTPulseBandwidth
+  description: |
+    The excitation bandwidth of the magnetization transfer pulse in Hertz (Hz).
+  type: number
+  unit: Hz
+MTPulseDuration:
+  name: MTPulseDuration
+  description: |
+    Duration of the magnetization transfer RF pulse in seconds.
+  type: number
+  unit: s
+MTPulseShape:
+  name: MTPulseShape
+  description: |
+    Shape of the magnetization transfer RF pulse waveform.
+    Accepted values: `"HARD"`, `"GAUSSIAN"`,
+    `"GAUSSHANN"` (gaussian pulse with Hanning window),
+    `"SINC"`, `"SINCHANN"` (sinc pulse with Hanning window),
+    `"SINCGAUSS"` (sinc pulse with Gaussian window), `"FERMI"`.
+  type: string
+  enum:
+  - HARD
+  - GAUSSIAN
+  - GAUSSHANN
+  - SINC
+  - SINCHANN
+  - SINCGAUSS
+  - FERMI
+MTState:
+  name: MTState
+  description: |
+    Boolean stating whether the magnetization transfer pulse is applied.
+    Corresponds to DICOM Tag 0018, 9020 `Magnetization Transfer`.
+  type: boolean
+MagneticFieldStrength:
+  name: MagneticFieldStrength
+  description: |
+    Nominal field strength of MR magnet in Tesla.
+    Corresponds to DICOM Tag 0018, 0087 `Magnetic Field Strength`.
+  type: number
+Manual:
+  name: Manual
+  description: |
+    Indicates if the segmentation was performed manually or via an automated
+    process.
+  type: boolean
+Manufacturer:
+  name: Manufacturer
+  description: |
+    Manufacturer of the equipment that produced the measurements.
+  type: string
+ManufacturersModelName:
+  name: ManufacturersModelName
+  description: |
+    Manufacturer's model name of the equipment that produced the measurements.
+  type: string
+MatrixCoilMode:
+  name: MatrixCoilMode
+  description: |
+    (If used)
+    A method for reducing the number of independent channels by combining in
+    analog the signals from multiple coil elements.
+    There are typically different default modes when using un-accelerated or
+    accelerated (for example, `"GRAPPA"`, `"SENSE"`) imaging.
+  type: string
+MaxMovement:
+  name: MaxMovement
+  description: |
+    Maximum head movement (in mm) detected during the recording,
+    as measured by the head localisation coils (for example, 4.8).
+  type: number
+  unit: mm
+MetaboliteAvail:
+  name: MetaboliteAvail
+  description: |
+    Boolean that specifies if metabolite measurements are available.
+    If `true`, the `metabolite_parent_fraction` column MUST be present in the
+    corresponding `*_blood.tsv` file.
+  type: boolean
+MetaboliteMethod:
+  name: MetaboliteMethod
+  description: |
+    Method used to measure metabolites.
+  type: string
+MetaboliteRecoveryCorrectionApplied:
+  name: MetaboliteRecoveryCorrectionApplied
+  description: |
+    Metabolite recovery correction from the HPLC, for tracers where it changes
+    with time postinjection.
+    If `true`, the `hplc_recovery_fractions` column MUST be present in the
+    corresponding `*_blood.tsv` file.
+  type: boolean
+MiscChannelCount:
+  name: MiscChannelCount
+  description: |
+    Number of miscellaneous analog channels for auxiliary signals.
+  type: integer
+  minimum: 0
+MixingTime:
+  name: MixingTime
+  description: |
+    In the context of a stimulated- and spin-echo 3D EPI sequence for B1+ mapping,
+    corresponds to the interval between spin- and stimulated-echo pulses.
+    In the context of a diffusion-weighted double spin-echo sequence,
+    corresponds to the interval between two successive diffusion sensitizing
+    gradients, specified in seconds.
+  type: number
+  unit: s
+ModeOfAdministration:
+  name: ModeOfAdministration
+  description: |
+    Mode of administration of the injection
+    (for example, `"bolus"`, `"infusion"`, or `"bolus-infusion"`).
+  type: string
+MolarActivity:
+  name: MolarActivity
+  description: |
+    Molar activity of compound injected.
+    Corresponds to DICOM Tag 0018, 1077 `Radiopharmaceutical Specific Activity`.
+  type: number
+MolarActivityMeasTime:
+  name: MolarActivityMeasTime
+  description: |
+    Time to which molar radioactivity measurement above applies in the default
+    unit `"hh:mm:ss"`.
+  type: string
+  pattern: ^(?:2[0-3]|[01][0-9]):[0-5][0-9]:[0-5][0-9]$
+MolarActivityUnits:
+  name: MolarActivityUnits
+  description: |
+    Unit of the specified molar radioactivity (for example, `"GBq/umol"`).
+  type: string
+  format: unit
+MultibandAccelerationFactor:
+  name: MultibandAccelerationFactor
+  description: |
+    The multiband factor, for multiband acquisitions.
+  type: number
+MultipartID:
+  name: MultipartID
+  description: |
+    A unique (per participant) label tagging DWI runs that are part of a
+    multipart scan.
+  type: string
+Name:
+  name: Name
+  description: |
+    Name of the dataset.
+  type: string
+NegativeContrast:
+  name: NegativeContrast
+  description: |
+    `true` or `false` value specifying whether increasing voxel intensity
+    (within sample voxels) denotes a decreased value with respect to the
+    contrast suffix.
+    This is commonly the case when Cerebral Blood Volume is estimated via
+    usage of a contrast agent in conjunction with a T2\* weighted acquisition
+    protocol.
+  type: boolean
+NonlinearGradientCorrection:
+  name: NonlinearGradientCorrection
+  description: |
+    Boolean stating if the image saved has been corrected for gradient
+    nonlinearities by the scanner sequence.
+  type: boolean
+NumberOfVolumesDiscardedByScanner:
+  name: NumberOfVolumesDiscardedByScanner
+  description: |
+    Number of volumes ("dummy scans") discarded by the scanner
+    (as opposed to those discarded by the user post hoc)
+    before saving the imaging file.
+    For example, a sequence that automatically discards the first 4 volumes
+    before saving would have this field as 4.
+    A sequence that doesn't discard dummy scans would have this set to 0.
+    Please note that the onsets recorded in the `events.tsv` file should always
+    refer to the beginning of the acquisition of the first volume in the
+    corresponding imaging file - independent of the value of
+    `NumberOfVolumesDiscardedByScanner` field.
+  type: integer
+  minimum: 0
+NumberOfVolumesDiscardedByUser:
+  name: NumberOfVolumesDiscardedByUser
+  description: |
+    Number of volumes ("dummy scans") discarded by the user before including the
+    file in the dataset.
+    If possible, including all of the volumes is strongly recommended.
+    Please note that the onsets recorded in the `events.tsv` file should always
+    refer to the beginning of the acquisition of the first volume in the
+    corresponding imaging file - independent of the value of
+    `NumberOfVolumesDiscardedByUser` field.
+  type: integer
+  minimum: 0
+NumberShots:
+  name: NumberShots
+  description: |
+    The number of RF excitations needed to reconstruct a slice or volume
+    (may be referred to as partition).
+    Please mind that this is not the same as Echo Train Length which denotes the
+    number of k-space lines collected after excitation in a multi-echo readout.
+    The data type array is applicable for specifying this parameter before and
+    after the k-space center is sampled.
+    Please see
+    [`NumberShots` metadata field]\
+    (/99-appendices/11-qmri.html#numbershots-metadata-field)
+    in the qMRI appendix for corresponding calculations.
+  anyOf:
+  - type: number
+  - type: array
+    items:
+      type: number
+OperatingSystem:
+  name: OperatingSystem
+  description: |
+    Operating system used to run the stimuli presentation software
+    (for formatting recommendations, see examples below this table).
+  type: string
+PASLType:
+  name: PASLType
+  description: |
+    Type of the labeling pulse of the `PASL` labeling,
+    for example `"FAIR"`, `"EPISTAR"`, or `"PICORE"`.
+  type: string
+PCASLType:
+  name: PCASLType
+  description: |
+    Type the gradient pulses used in the `"control"` condition:
+    `"balanced"` or `"unbalanced"`.
+  type: string
+  enum:
+  - balanced
+  - unbalanced
+ParallelAcquisitionTechnique:
+  name: ParallelAcquisitionTechnique
+  description: |
+    The type of parallel imaging used (for example `"GRAPPA"`, `"SENSE"`).
+    Corresponds to DICOM Tag 0018, 9078 `Parallel Acquisition Technique`.
+  type: string
+ParallelReductionFactorInPlane:
+  name: ParallelReductionFactorInPlane
+  description: |
+    The parallel imaging (for instance, GRAPPA) factor.
+    Use the denominator of the fraction of k-space encoded for each slice.
+    For example, 2 means half of k-space is encoded.
+    Corresponds to DICOM Tag 0018, 9069 `Parallel Reduction Factor In-plane`.
+  type: number
+PartialFourier:
+  name: PartialFourier
+  description: |
+    The fraction of partial Fourier information collected.
+    Corresponds to DICOM Tag 0018, 9081 `Partial Fourier`.
+  type: number
+PartialFourierDirection:
+  name: PartialFourierDirection
+  description: |
+    The direction where only partial Fourier information was collected.
+    Corresponds to DICOM Tag 0018, 9036 `Partial Fourier Direction`.
+  type: string
+PharmaceuticalDoseAmount:
+  name: PharmaceuticalDoseAmount
+  description: |
+    Dose amount of pharmaceutical coadministered with tracer.
+  anyOf:
+  - type: number
+  - type: array
+    items:
+      type: number
+PharmaceuticalDoseRegimen:
+  name: PharmaceuticalDoseRegimen
+  description: |
+    Details of the pharmaceutical dose regimen.
+    Either adequate description or short-code relating to regimen documented
+    elsewhere (for example, `"single oral bolus"`).
+  type: string
+PharmaceuticalDoseTime:
+  name: PharmaceuticalDoseTime
+  description: |
+    Time of administration of pharmaceutical dose, relative to time zero.
+    For an infusion, this should be a vector with two elements specifying the
+    start and end of the infusion period. For more complex dose regimens,
+    the regimen description should be complete enough to enable unambiguous
+    interpretation of `PharmaceuticalDoseTime`.
+    Unit format of the specified pharmaceutical dose time MUST be seconds.
+  anyOf:
+  - type: number
+    unit: s
+  - type: array
+    items:
+      type: number
+      unit: s
+PharmaceuticalDoseUnits:
+  name: PharmaceuticalDoseUnits
+  description: |
+    Unit format relating to pharmaceutical dose
+    (for example, `"mg"` or `"mg/kg"`).
+  type: string
+  format: unit
+PharmaceuticalName:
+  name: PharmaceuticalName
+  description: |
+    Name of pharmaceutical coadministered with tracer.
+  type: string
+PhaseEncodingDirection:
+  name: PhaseEncodingDirection
+  description: |
+    Possible values: `"i"`, `"j"`, `"k"`, `"i-"`, `"j-"`, `"k-"`.
+    The letters `i`, `j`, `k` correspond to the first, second and third axis of
+    the data in the NIFTI file.
+    The polarity of the phase encoding is assumed to go from zero index to
+    maximum index unless `-` sign is present
+    (then the order is reversed - starting from the highest index instead of
+    zero).
+    `PhaseEncodingDirection` is defined as the direction along which phase is was
+    modulated which may result in visible distortions.
+    Note that this is not the same as the DICOM term
+    `InPlanePhaseEncodingDirection` which can have `ROW` or `COL` values.
+  type: string
+  enum:
+  - i
+  - j
+  - k
+  - i-
+  - j-
+  - k-
+PlasmaAvail:
+  name: PlasmaAvail
+  description: |
+    Boolean that specifies if plasma measurements are available.
+  type: boolean
+PlasmaFreeFraction:
+  name: PlasmaFreeFraction
+  description: |
+    Measured free fraction in plasma, meaning the concentration of free compound
+    in plasma divided by total concentration of compound in plasma
+    (Units: 0-100%).
+  type: number
+  minimum: 0
+  maximum: 100
+PlasmaFreeFractionMethod:
+  name: PlasmaFreeFractionMethod
+  description: |
+    Method used to estimate free fraction.
+  type: string
+PostLabelingDelay:
+  name: PostLabelingDelay
+  description: |
+    This is the postlabeling delay (PLD) time, in seconds, after the end of the
+    labeling (for `"CASL"` or `"PCASL"`) or middle of the labeling pulse
+    (for `"PASL"`) until the middle of the excitation pulse applied to the
+    imaging slab (for 3D acquisition) or first slice (for 2D acquisition).
+    Can be a number (for a single-PLD time series) or an array of numbers
+    (for multi-PLD and Look-Locker).
+    In the latter case, the array of numbers contains the PLD of each volume,
+    namely each `control` and `label`, in the acquisition order.
+    Any image within the time-series without a PLD, for example an `m0scan`,
+    is indicated by a zero.
+    Based on DICOM Tags 0018, 9079 `Inversion Times` and 0018, 0082
+    `InversionTime`.
+  anyOf:
+  - type: number
+    exclusiveMinimum: 0
+    unit: s
+  - type: array
+    items:
+      type: number
+      exclusiveMinimum: 0
+      unit: s
+PowerLineFrequency:
+  name: PowerLineFrequency
+  description: |
+    Frequency (in Hz) of the power grid at the geographical location of the
+    instrument (for example, `50` or `60`).
+  anyOf:
+  - type: number
+    exclusiveMinimum: 0
+    unit: Hz
+  - type: string
+    enum:
+    - n/a
+PromptRate:
+  name: PromptRate
+  description: |
+    Prompt rate for each frame (same units as `Units`, for example, `"Bq/mL"`).
+  type: array
+  items:
+    type: number
+PulseSequenceDetails:
+  name: PulseSequenceDetails
+  description: |
+    Information beyond pulse sequence type that identifies the specific pulse
+    sequence used (for example,
+    `"Standard Siemens Sequence distributed with the VB17 software"`,
+    `"Siemens WIP ### version #.##,"` or
+    `"Sequence written by X using a version compiled on MM/DD/YYYY"`).
+  type: string
+PulseSequenceType:
+  name: PulseSequenceType
+  description: |
+    A general description of the pulse sequence used for the scan
+    (for example, `"MPRAGE"`, `"Gradient Echo EPI"`, `"Spin Echo EPI"`,
+    `"Multiband gradient echo EPI"`).
+  type: string
+Purity:
+  name: Purity
+  description: |
+    Purity of the radiolabeled compound (between 0 and 100%).
+  type: number
+  minimum: 0
+  maximum: 100
+RandomRate:
+  name: RandomRate
+  description: |
+    Random rate for each frame (same units as `Units`, for example, `"Bq/mL"`).
+  type: array
+  items:
+    type: number
+RawSources:
+  name: RawSources
+  description: |
+    A list of paths relative to dataset root pointing to the BIDS-Raw file(s)
+    that were used in the creation of this derivative.
+  type: array
+  items:
+    type: string
+    format: dataset_relative
+ReceiveCoilActiveElements:
+  name: ReceiveCoilActiveElements
+  description: |
+    Information describing the active/selected elements of the receiver coil.
+    This doesn't correspond to a tag in the DICOM ontology.
+    The vendor-defined terminology for active coil elements can go in this field.
+  type: string
+ReceiveCoilName:
+  name: ReceiveCoilName
+  description: |
+    Information describing the receiver coil.
+    Corresponds to DICOM Tag 0018, 1250 `Receive Coil Name`,
+    although not all vendors populate that DICOM Tag,
+    in which case this field can be derived from an appropriate
+    private DICOM field.
+  type: string
+ReconFilterSize:
+  name: ReconFilterSize
+  description: |
+    Kernel size of post-recon filter (FWHM) in default units `"mm"`.
+  anyOf:
+  - type: number
+    unit: mm
+  - type: array
+    items:
+      type: number
+      unit: mm
+ReconFilterType:
+  name: ReconFilterType
+  description: |
+    Type of post-recon smoothing (for example, `["Shepp"]`).
+  anyOf:
+  - type: string
+  - type: array
+    items:
+      type: string
+ReconMethodImplementationVersion:
+  name: ReconMethodImplementationVersion
+  description: |
+    Identification for the software used, such as name and version.
+  type: string
+ReconMethodName:
+  name: ReconMethodName
+  description: |
+    Reconstruction method or algorithm (for example, `"3d-op-osem"`).
+  type: string
+ReconMethodParameterLabels:
+  name: ReconMethodParameterLabels
+  description: |
+    Names of reconstruction parameters (for example, `["subsets", "iterations"]`).
+  type: array
+  items:
+    type: string
+ReconMethodParameterUnits:
+  name: ReconMethodParameterUnits
+  description: |
+    Unit of reconstruction parameters (for example, `["none", "none"]`).
+  type: array
+  items:
+    type: string
+    format: unit
+ReconMethodParameterValues:
+  name: ReconMethodParameterValues
+  description: |
+    Values of reconstruction parameters (for example, `[21, 3]`).
+  type: array
+  items:
+    type: number
+RecordingDuration:
+  name: RecordingDuration
+  description: |
+    Length of the recording in seconds (for example, `3600`).
+  type: number
+  unit: s
+RecordingType:
+  name: RecordingType
+  description: |
+    Defines whether the recording is `"continuous"`, `"discontinuous"` or
+    `"epoched"`, where `"epoched"` is limited to time windows about events of
+    interest (for example, stimulus presentations or subject responses).
+  type: string
+  enum:
+  - continuous
+  - epoched
+  - discontinuous
+ReferencesAndLinks:
+  name: ReferencesAndLinks
+  description: |
+    List of references to publications that contain information on the dataset.
+    A reference may be textual or a
+    [URI](/02-common-principles.html#uniform-resource-indicator).
+  items:
+    type: string
+  type: array
+RepetitionTime:
+  name: RepetitionTime
+  description: |
+    The time in seconds between the beginning of an acquisition of one volume
+    and the beginning of acquisition of the volume following it (TR).
+    When used in the context of functional acquisitions this parameter best
+    corresponds to
+    [DICOM Tag 0020, 0110](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0020,0110)):
+    the "time delta between images in a
+    dynamic of functional set of images" but may also be found in
+    [DICOM Tag 0018, 0080](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0080)):
+    "the period of time in msec between the beginning
+    of a pulse sequence and the beginning of the succeeding
+    (essentially identical) pulse sequence".
+    This definition includes time between scans (when no data has been acquired)
+    in case of sparse acquisition schemes.
+    This value MUST be consistent with the 'pixdim[4]' field (after accounting
+    for units stored in 'xyzt_units' field) in the NIfTI header.
+    This field is mutually exclusive with VolumeTiming.
+  type: number
+  exclusiveMinimum: 0
+  unit: s
+RepetitionTimeExcitation:
+  name: RepetitionTimeExcitation
+  description: |
+    The interval, in seconds, between two successive excitations.
+    [DICOM Tag 0018, 0080](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0080)
+    best refers to this parameter.
+    This field may be used together with the `RepetitionTimePreparation` for
+    certain use cases, such as
+    [MP2RAGE](https://doi.org/10.1016/j.neuroimage.2009.10.002).
+    Use `RepetitionTimeExcitation` (in combination with
+    `RepetitionTimePreparation` if needed) for anatomy imaging data rather than
+    `RepetitionTime` as it is already defined as the amount of time that it takes
+    to acquire a single volume in the
+    [task imaging data](/04-modality-specific-files/01-magnetic-resonance-\
+    imaging-data.html#task-including-resting-state-imaging-data)
+    section.
+  type: number
+  minimum: 0
+  unit: s
+RepetitionTimePreparation:
+  name: RepetitionTimePreparation
+  description: |
+    The interval, in seconds, that it takes a preparation pulse block to
+    re-appear at the beginning of the succeeding (essentially identical) pulse
+    sequence block.
+    The data type number may apply to files from any MRI modality concerned with
+    a single value for this field.
+    The data type array provides a value for each volume in a 4D dataset and
+    should only be used when the volume timing is critical for interpretation of
+    the data, such as in
+    [ASL](/04-modality-specific-files/01-magnetic-resonance-imaging-data.html\
+    #arterial-spin-labeling-perfusion-data).
+  anyOf:
+  - type: number
+    minimum: 0
+    unit: s
+  - type: array
+    items:
+      type: number
+      minimum: 0
+      unit: s
+Resolution:
+  name: Resolution
+  description: |
+    Specifies the interpretation of the resolution keyword.
+    If an object is used, then the keys should be values for the ``res`` entity
+    and values should be descriptions of those ``res`` values.
+  anyOf:
+  - type: string
+  - type: object
+    additionalProperties:
+      type: string
+SEEGChannelCount:
+  name: SEEGChannelCount
+  description: |
+    Number of SEEG channels.
+  type: integer
+  minimum: 0
+SampleOrigin:
+  name: SampleOrigin
+  description: |
+    Describes from which tissue the genetic information was extracted.
+    Values MUST be one of `"blood"`, `"saliva"`, `"brain"`, `"csf"`,
+    `"breast milk"`, `"bile"`, `"amniotic fluid"`, `"other biospecimen"`.
+  type: string
+  enum:
+  - blood
+  - saliva
+  - brain
+  - csf
+  - breast milk
+  - bile
+  - amniotic fluid
+  - other biospecimen
+SamplingFrequency:
+  name: SamplingFrequency
+  description: |
+    Sampling frequency (in Hz) of all the data in the recording,
+    regardless of their type (for example, `2400`).
+  type: number
+  unit: Hz
+ScaleFactor:
+  name: ScaleFactor
+  description: |
+    Scale factor for each frame.
+  type: array
+  items:
+    type: number
+ScanDate:
+  name: ScanDate
+  description: |
+    Date of scan in the format `"YYYY-MM-DD[Z]"`.
+    This field is DEPRECATED, and this metadata SHOULD be recorded in the `acq_time` column of the
+    corresponding [Scans file](/03-modality-agnostic-files.html#scans-file).
+  type: string
+  format: date
+ScanOptions:
+  name: ScanOptions
+  description: |
+    Parameters of ScanningSequence.
+    Corresponds to DICOM Tag 0018, 0022 `Scan Options`.
+  anyOf:
+  - type: string
+  - type: array
+    items:
+      type: string
+ScanStart:
+  name: ScanStart
+  description: |
+    Time of start of scan with respect to `TimeZero` in the default unit seconds.
+  type: number
+  unit: s
+ScanningSequence:
+  name: ScanningSequence
+  description: |
+    Description of the type of data acquired.
+    Corresponds to DICOM Tag 0018, 0020 `Scanning Sequence`.
+  anyOf:
+  - type: string
+  - type: array
+    items:
+      type: string
+ScatterFraction:
+  name: ScatterFraction
+  description: |
+    Scatter fraction for each frame (Units: 0-100%).
+  type: array
+  items:
+    type: number
+    minimum: 0
+    maximum: 100
+SequenceName:
+  name: SequenceName
+  description: |
+    Manufacturer's designation of the sequence name.
+    Corresponds to DICOM Tag 0018, 0024 `Sequence Name`.
+  type: string
+SequenceVariant:
+  name: SequenceVariant
+  description: |
+    Variant of the ScanningSequence.
+    Corresponds to DICOM Tag 0018, 0021 `Sequence Variant`.
+  anyOf:
+  - type: string
+  - type: array
+    items:
+      type: string
+SinglesRate:
+  name: SinglesRate
+  description: |
+    Singles rate for each frame (same units as `Units`, for example, `"Bq/mL"`).
+  type: array
+  items:
+    type: number
+SkullStripped:
+  name: SkullStripped
+  description: |
+    Whether the volume was skull stripped (non-brain voxels set to zero) or not.
+  type: boolean
+SliceEncodingDirection:
+  name: SliceEncodingDirection
+  description: |
+    Possible values: `"i"`, `"j"`, `"k"`, `"i-"`, `"j-"`, `"k-"`
+    (the axis of the NIfTI data along which slices were acquired,
+    and the direction in which `SliceTiming` is defined with respect to).
+    `i`, `j`, `k` identifiers correspond to the first, second and third axis of
+    the data in the NIfTI file.
+    A `-` sign indicates that the contents of `SliceTiming` are defined in
+    reverse order - that is, the first entry corresponds to the slice with the
+    largest index, and the final entry corresponds to slice index zero.
+    When present, the axis defined by `SliceEncodingDirection` needs to be
+    consistent with the `slice_dim` field in the NIfTI header.
+    When absent, the entries in `SliceTiming` must be in the order of increasing
+    slice index as defined by the NIfTI header.
+  type: string
+  enum:
+  - i
+  - j
+  - k
+  - i-
+  - j-
+  - k-
+SliceTiming:
+  name: SliceTiming
+  description: |
+    The time at which each slice was acquired within each volume (frame) of the
+    acquisition.
+    Slice timing is not slice order -- rather, it is a list of times containing
+    the time (in seconds) of each slice acquisition in relation to the beginning
+    of volume acquisition.
+    The list goes through the slices along the slice axis in the slice encoding
+    dimension (see below).
+    Note that to ensure the proper interpretation of the `SliceTiming` field,
+    it is important to check if the OPTIONAL `SliceEncodingDirection` exists.
+    In particular, if `SliceEncodingDirection` is negative,
+    the entries in `SliceTiming` are defined in reverse order with respect to the
+    slice axis, such that the final entry in the `SliceTiming` list is the time
+    of acquisition of slice 0. Without this parameter slice time correction will
+    not be possible.
+  type: array
+  items:
+    type: number
+    minimum: 0
+    unit: s
+SoftwareFilters:
+  name: SoftwareFilters
+  description: |
+    [Object](https://www.json.org/json-en.html)
+    of temporal software filters applied, or `"n/a"` if the data is
+    not available.
+    Each key:value pair in the JSON object is a name of the filter and an object
+    in which its parameters are defined as key:value pairs
+    (for example, `{"Anti-aliasing filter":
+    {"half-amplitude cutoff (Hz)": 500, "Roll-off": "6dB/Octave"}}`).
+  anyOf:
+  - type: object
+    additionalProperties:
+      type: object
+  - type: string
+    enum:
+    - n/a
+SoftwareName:
+  name: SoftwareName
+  description: |
+    Name of the software that was used to present the stimuli.
+  type: string
+SoftwareRRID:
+  name: SoftwareRRID
+  description: |
+    [Research Resource Identifier](https://scicrunch.org/resources) of the
+    software that was used to present the stimuli.
+    Examples: The RRID for Psychtoolbox is 'SCR_002881',
+    and that of PsychoPy is 'SCR_006571'.
+  type: string
+  pattern: .+_.+
+SoftwareVersion:
+  name: SoftwareVersion
+  description: |
+    Version of the software that was used to present the stimuli.
+  type: string
+SoftwareVersions:
+  name: SoftwareVersions
+  description: |
+    Manufacturer's designation of software version of the equipment that produced
+    the measurements.
+  type: string
+SourceDatasets:
+  name: SourceDatasets
+  description: |
+    Used to specify the locations and relevant attributes of all source datasets.
+    Valid keys in each object include `URL`, `DOI` (see
+    [URI](/02-common-principles.html#uniform-resource-indicator)), and
+    `Version` with
+    [string](https://www.w3schools.com/js/js_json_datatypes.asp)
+    values.
+  type: array
+  items:
+    type: object
+    properties:
+      URL:
+        type: string
+        format: uri
+      DOI:
+        type: string
+      Version:
+        type: string
+Sources:
+  name: Sources
+  description: |
+    A list of files with the paths specified relative to dataset root;
+    these files were directly used in the creation of this derivative data file.
+    For example, if a derivative A is used in the creation of another
+    derivative B, which is in turn used to generate C in a chain of A->B->C,
+    C should only list B in `Sources`, and B should only list A in `Sources`.
+    However, in case both X and Y are directly used in the creation of Z,
+    then Z should list X and Y in `Sources`,
+    regardless of whether X was used to generate Y.
+  type: array
+  items:
+    type: string
+    format: dataset_relative
+SpatialReference:
+  name: SpatialReference
+  description: |
+    For images with a single reference, the value MUST be a single string.
+    For images with multiple references, such as surface and volume references,
+    a JSON object MUST be used.
+  anyOf:
+  - type: string
+    enum:
+    - orig
+  - type: string
+    format: uri
+  - type: string
+    format: dataset_relative
+  - type: object
+    additionalProperties:
+      anyOf:
+      - type: string
+        enum:
+        - orig
+      - type: string
+        format: uri
+      - type: string
+        format: dataset_relative
+SpecificRadioactivity:
+  name: SpecificRadioactivity
+  description: |
+    Specific activity of compound injected.
+    **Note this is not required for an FDG acquisition, since it is not available,
+    and SHOULD be set to `"n/a"`**.
+  anyOf:
+  - type: number
+  - type: string
+    enum:
+    - n/a
+SpecificRadioactivityMeasTime:
+  name: SpecificRadioactivityMeasTime
+  description: |
+    Time to which specific radioactivity measurement above applies in the default
+    unit `"hh:mm:ss"`.
+  type: string
+  pattern: ^(?:2[0-3]|[01][0-9]):[0-5][0-9]:[0-5][0-9]$
+SpecificRadioactivityUnits:
+  name: SpecificRadioactivityUnits
+  description: |
+    Unit format of specified specific radioactivity (for example, `"Bq/g"`).
+    **Note this is not required for an FDG acquisition, since it is not available,
+    and SHOULD be set to `"n/a"`**.
+  anyOf:
+  - type: string
+    format: unit
+  - type: string
+    enum:
+    - n/a
+SpoilingGradientDuration:
+  name: SpoilingGradientDuration
+  description: |
+    The duration of the spoiler gradient lobe in seconds.
+    The duration of a trapezoidal lobe is defined as the summation of ramp-up
+    and plateau times.
+  type: number
+  unit: s
+SpoilingGradientMoment:
+  name: SpoilingGradientMoment
+  description: |
+    Zeroth moment of the spoiler gradient lobe in
+    millitesla times second per meter (mT.s/m).
+  type: number
+  unit: mT.s/m
+SpoilingRFPhaseIncrement:
+  name: SpoilingRFPhaseIncrement
+  description: |
+    The amount of incrementation described in degrees,
+    which is applied to the phase of the excitation pulse at each TR period for
+    achieving RF spoiling.
+  type: number
+  unit: degrees
+SpoilingState:
+  name: SpoilingState
+  description: |
+    Boolean stating whether the pulse sequence uses any type of spoiling
+    strategy to suppress residual transverse magnetization.
+  type: boolean
+SpoilingType:
+  name: SpoilingType
+  description: |
+    Specifies which spoiling method(s) are used by a spoiled sequence.
+    Accepted values: `"RF"`, `"GRADIENT"` or `"COMBINED"`.
+  type: string
+  enum:
+  - RF
+  - GRADIENT
+  - COMBINED
+StartTime:
+  name: StartTime
+  description: |
+    Start time in seconds in relation to the start of acquisition of the first
+    data sample in the corresponding neural dataset (negative values are allowed).
+  type: number
+  unit: s
+StationName:
+  name: StationName
+  description: |
+    Institution defined name of the machine that produced the measurements.
+    Corresponds to DICOM Tag 0008, 1010 `Station Name`.
+  type: string
+StimulusPresentation:
+  name: StimulusPresentation
+  description: |
+    Object containing key value pairs related to the software used to present
+    the stimuli during the experiment, specifically:
+    `OperatingSystem`, `SoftwareName`, `SoftwareRRID`, `SoftwareVersion` and
+    `Code`.
+    See table below for more information.
+  type: object
+  properties:
+    OperatingSystem:
+      $ref: OperatingSystem
+    SoftwareName:
+      $ref: SoftwareName
+    SoftwareRRID:
+      $ref: SoftwareRRID
+    SoftwareVersion:
+      $ref: SoftwareVersion
+    Code:
+      $ref: Code
+SubjectArtefactDescription:
+  name: SubjectArtefactDescription
+  description: |
+    Freeform description of the observed subject artefact and its possible cause
+    (for example, `"Vagus Nerve Stimulator"`, `"non-removable implant"`).
+    If this field is set to `"n/a"`, it will be interpreted as absence of major
+    source of artifacts except cardiac and blinks.
+  type: string
+TaskDescription:
+  name: TaskDescription
+  description: |
+    Longer description of the task.
+  type: string
+TaskName:
+  name: TaskName
+  description: |
+    Name of the task.
+    No two tasks should have the same name.
+    The task label included in the file name is derived from this TaskName field
+    by removing all non-alphanumeric (`[a-zA-Z0-9]`) characters.
+    For example `TaskName` `"faces n-back"` will correspond to task label
+    `facesnback`.
+  type: string
+TermURL:
+  name: TermURL
+  description: |
+    URL pointing to a formal definition of this type of data in an ontology
+    available on the web.
+  type: string
+TimeZero:
+  name: TimeZero
+  description: |
+    Time zero to which all scan and/or blood measurements have been adjusted to,
+    in the unit "hh:mm:ss".
+    This should be equal to `InjectionStart` or `ScanStart`.
+  type: string
+  pattern: ^(?:2[0-3]|[01][0-9]):[0-5][0-9]:[0-5][0-9]$
+TissueOrigin:
+  name: TissueOrigin
+  description: |
+    Describes the type of tissue analyzed for `SampleOrigin` `brain`.
+    Values MUST be one of `"gray matter"`, `"white matter"`, `"csf"`,
+    `"meninges"`, `"macrovascular"` or `microvascular`.
+  type: string
+  enum:
+  - gray matter
+  - white matter
+  - csf
+  - meninges
+  - macrovascular
+  - microvascular
+TotalAcquiredPairs:
+  name: TotalAcquiredPairs
+  description: |
+    The total number of acquired `control`-`label` pairs.
+    A single pair consists of a single `control` and a single `label` image.
+  type: number
+  exclusiveMinimum: 0
+TotalReadoutTime:
+  name: TotalReadoutTime
+  description: |
+    This is actually the "effective" total readout time,
+    defined as the readout duration, specified in seconds,
+    that would have generated data with the given level of distortion.
+    It is NOT the actual, physical duration of the readout train.
+    If `EffectiveEchoSpacing` has been properly computed,
+    it is just `EffectiveEchoSpacing * (ReconMatrixPE - 1)`.
+  type: number
+  unit: s
+TracerMolecularWeight:
+  name: TracerMolecularWeight
+  description: |
+    Accurate molecular weight of the tracer used.
+  type: number
+TracerMolecularWeightUnits:
+  name: TracerMolecularWeightUnits
+  description: |
+    Unit of the molecular weights measurement (for example, `"g/mol"`).
+  type: string
+  format: unit
+TracerName:
+  name: TracerName
+  description: |
+    Name of the tracer compound used (for example, `"CIMBI-36"`)
+  type: string
+TracerRadLex:
+  name: TracerRadLex
+  description: |
+    ID of the tracer compound from the RadLex Ontology.
+  type: string
+TracerRadionuclide:
+  name: TracerRadionuclide
+  description: |
+    Radioisotope labelling tracer (for example, `"C11"`).
+  type: string
+TracerSNOMED:
+  name: TracerSNOMED
+  description: |
+    ID of the tracer compound from the SNOMED Ontology
+    (subclass of Radioactive isotope).
+  type: string
+TriggerChannelCount:
+  name: TriggerChannelCount
+  description: |
+    Number of channels for digital (TTL bit level) triggers.
+  type: integer
+  minimum: 0
+TubingLength:
+  name: TubingLength
+  description: |
+    The length of the blood tubing, from the subject to the detector in meters.
+  type: number
+  unit: m
+TubingType:
+  name: TubingType
+  description: |
+    Description of the type of tubing used, ideally including the material and
+    (internal) diameter.
+  type: string
+Type:
+  name: Type
+  description: |
+    Short identifier of the mask.
+    Reserved values: `Brain` - brain mask, `Lesion` - lesion mask,
+    `Face` - face mask, `ROI` - ROI mask
+  type: string
+  enum:
+  - Brain
+  - Lesion
+  - Face
+  - ROI
+Units:
+  name: Units
+  description: |
+    Measurement units for the associated file.
+    SI units in CMIXF formatting are RECOMMENDED
+    (see [Units](/02-common-principles.html#units)).
+  type: string
+  format: unit
+VascularCrushing:
+  name: VascularCrushing
+  description: |
+    Boolean indicating if Vascular Crushing is used.
+    Corresponds to DICOM Tag 0018, 9259 `ASL Crusher Flag`.
+  type: boolean
+VascularCrushingVENC:
+  name: VascularCrushingVENC
+  description: |
+    The crusher gradient strength, in centimeters per second.
+    Specify either one number for the total time-series, or provide an array of
+    numbers, for example when using QUASAR, using the value zero to identify
+    volumes for which `VascularCrushing` was turned off.
+    Corresponds to DICOM Tag 0018, 925A `ASL Crusher Flow Limit`.
+  anyOf:
+  - type: number
+    unit: cm/s
+  - type: array
+    items:
+      type: number
+      unit: cm/s
+VolumeTiming:
+  name: VolumeTiming
+  description: |
+    The time at which each volume was acquired during the acquisition.
+    It is described using a list of times referring to the onset of each volume
+    in the BOLD series.
+    The list must have the same length as the BOLD series,
+    and the values must be non-negative and monotonically increasing.
+    This field is mutually exclusive with `RepetitionTime` and `DelayTime`.
+    If defined, this requires acquisition time (TA) be defined via either
+    `SliceTiming` or `AcquisitionDuration` be defined.
+  type: array
+  minItems: 1
+  items:
+    type: number
+    unit: s
+WholeBloodAvail:
+  name: WholeBloodAvail
+  description: |
+    Boolean that specifies if whole blood measurements are available.
+    If `true`, the `whole_blood_radioactivity` column MUST be present in the
+    corresponding `*_blood.tsv` file.
+  type: boolean
+WithdrawalRate:
+  name: WithdrawalRate
+  description: |
+    The rate at which the blood was withdrawn from the subject.
+    The unit of the specified withdrawal rate should be in `"mL/s"`.
+  type: number
+  unit: mL/s
+_CoordUnits:
+  type: string
+  enum:
+  - m
+  - mm
+  - cm
+  - n/a
+_EEGCoordSys:
+  type: string
+  enum:
+  - CapTrak
+  - EEGLAB
+  - EEGLAB-HJ
+  - Other
+_GeneticLevelEnum:
+  type: string
+  enum:
+  - Genetic
+  - Genomic
+  - Epigenomic
+  - Transcriptomic
+  - Metabolomic
+  - Proteomic
+_LandmarkCoordinates:
+  type: object
+  additionalProperties:
+    type: array
+    items:
+      type: number
+    minItems: 3
+    maxItems: 3
+_MEGCoordSys:
+  type: string
+  enum:
+  - CTF
+  - ElektaNeuromag
+  - 4DBti
+  - KitYokogawa
+  - ChietiItab
+  - Other
+_StandardTemplateCoordSys:
+  type: string
+  enum:
+  - ICBM452AirSpace
+  - ICBM452Warp5Space
+  - IXI549Space
+  - fsaverage
+  - fsaverageSym
+  - fsLR
+  - MNIColin27
+  - MNI152Lin
+  - MNI152NLin2009aSym
+  - MNI152NLin2009bSym
+  - MNI152NLin2009cSym
+  - MNI152NLin2009aAsym
+  - MNI152NLin2009bAsym
+  - MNI152NLin2009cAsym
+  - MNI152NLin6Sym
+  - MNI152NLin6ASym
+  - MNI305
+  - NIHPD
+  - OASIS30AntsOASISAnts
+  - OASIS30Atropos
+  - Talairach
+  - UNCInfant
+_StandardTemplateDeprecatedCoordSys:
+  type: string
+  enum:
+  - fsaverage3
+  - fsaverage4
+  - fsaverage5
+  - fsaverage6
+  - fsaveragesym
+  - UNCInfant0V21
+  - UNCInfant1V21
+  - UNCInfant2V21
+  - UNCInfant0V22
+  - UNCInfant1V22
+  - UNCInfant2V22
+  - UNCInfant0V23
+  - UNCInfant1V23
+  - UNCInfant2V23
+_iEEGCoordSys:
+  type: string
+  enum:
+  - Pixels
+  - ACPC
+  - Other
+iEEGCoordinateProcessingDescription:
+  name: iEEGCoordinateProcessingDescription
+  description: |
+    Has any post-processing (such as projection) been done on the electrode
+    positions (for example, `"surface_projection"`, `"none"`).
+  type: string
+iEEGCoordinateProcessingReference:
+  name: iEEGCoordinateProcessingReference
+  description: |
+    A reference to a paper that defines in more detail the method used to
+    localize the electrodes and to post-process the electrode positions.
+  type: string
+iEEGCoordinateSystem:
+  name: iEEGCoordinateSystem
+  description: |
+    Defines the coordinate system for the iEEG sensors.
+    See
+    [Appendix VIII](/99-appendices/08-coordinate-systems.html)
+    for a list of restricted keywords for coordinate systems.
+    If `"Other"`, provide definition of the coordinate system in
+    `iEEGCoordinateSystemDescription`.
+    If positions correspond to pixel indices in a 2D image
+    (of either a volume-rendering, surface-rendering, operative photo, or
+    operative drawing), this MUST be `"Pixels"`.
+    For more information, see the section on
+    [2D coordinate systems](/04-modality-specific-files/04-intracranial\
+    -electroencephalography.html#allowed-2d-coordinate-systems).
+  anyOf:
+  - $ref: _iEEGCoordSys
+  - $ref: _StandardTemplateCoordSys
+  - $ref: _StandardTemplateDeprecatedCoordSys
+iEEGCoordinateSystemDescription:
+  name: iEEGCoordinateSystemDescription
+  description: |
+    Free-form text description of the coordinate system.
+    May also include a link to a documentation page or paper describing the
+    system in greater detail.
+  type: string
+iEEGCoordinateUnits:
+  name: iEEGCoordinateUnits
+  description: |
+    Units of the `*_electrodes.tsv`, MUST be `"m"`, `"mm"`, `"cm"` or `"pixels"`.
+    MUST be `"pixels"` if `iEEGCoordinateSystem` is `Pixels`.
+  type: string
+  enum:
+  - m
+  - mm
+  - cm
+  - pixels
+  - n/a
+iEEGElectrodeGroups:
+  name: iEEGElectrodeGroups
+  description: |
+    Field to describe the way electrodes are grouped into strips, grids or depth
+    probes.
+    For example, `"grid1: 10x8 grid on left temporal pole, strip2: 1x8 electrode
+    strip on xxx"`.
+  type: string
+iEEGGround:
+  name: iEEGGround
+  description: |
+    Description of the location of the ground electrode
+    (`"placed on right mastoid (M2)"`).
+  type: string
+iEEGPlacementScheme:
+  name: iEEGPlacementScheme
+  description: |
+    Freeform description of the placement of the iEEG electrodes.
+    Left/right/bilateral/depth/surface
+    (for example, `"left frontal grid and bilateral hippocampal depth"` or
+    `"surface strip and STN depth"` or
+    `"clinical indication bitemporal, bilateral temporal strips and left grid"`).
+  type: string
+iEEGReference:
+  name: iEEGReference
+  description: |
+    General description of the reference scheme used and (when applicable) of
+    location of the reference electrode in the raw recordings
+    (for example, `"left mastoid"`, `"bipolar"`,
+    `"T01"` for electrode with name T01,
+    `"intracranial electrode on top of a grid, not included with data"`,
+    `"upside down electrode"`).
+    If different channels have a different reference,
+    this field should have a general description and the channel specific
+    reference should be defined in the channels.tsv file.
+  type: string
diff --git a/src/schema/objects/modalities.yaml b/src/schema/objects/modalities.yaml
new file mode 100644
index 0000000000..56b083425d
--- /dev/null
+++ b/src/schema/objects/modalities.yaml
@@ -0,0 +1,26 @@
+---
+# This file describes modalities supported by BIDS.
+mri:
+  name: Magnetic Resonance Imaging
+  description: |
+    Data acquired with an MRI scanner.
+eeg:
+  name: Electroencephalography
+  description: |
+    Data acquired with EEG.
+ieeg:
+  name: Intracranial Electroencephalography
+  description: |
+    Data acquired with iEEG.
+meg:
+  name: Magnetoencephalography
+  description: |
+    Data acquired with an MEG scanner.
+beh:
+  name: Behavioral experiments
+  description: |
+    Behavioral data acquired without accompanying neuroimaging data.
+pet:
+  name: Positron Emission Tomography
+  description: |
+    Data acquired with PET.
diff --git a/src/schema/objects/suffixes.yaml b/src/schema/objects/suffixes.yaml
new file mode 100644
index 0000000000..de492e5a1f
--- /dev/null
+++ b/src/schema/objects/suffixes.yaml
@@ -0,0 +1,560 @@
+---
+# This file defines valid BIDS file suffixes.
+# For rules regarding how suffixes relate to datatypes, see files in `rules/datatypes/`.
+Chimap:
+  name: Quantitative susceptibility map (QSM)
+  description: |
+    In parts per million (ppm).
+    QSM allows for determining the underlying magnetic susceptibility of tissue
+    (Chi)
+    ([Wang & Liu, 2014](https://onlinelibrary.wiley.com/doi/10.1002/mrm.25358)).
+    Chi maps are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+  unit: ppm
+FLAIR:
+  name: Fluid attenuated inversion recovery image
+  description: |
+    In arbitrary units (arbitrary).
+    Structural images with predominant T2 contribution (also known as T2-FLAIR),
+    in which signal from fluids (for example, CSF) is nulled out by adjusting
+    inversion time, coupled with notably long repetition and echo times.
+  unit: arbitrary
+FLASH:
+  name: Fast-Low-Angle-Shot image
+  description: |
+    FLASH (Fast-Low-Angle-Shot) is a vendor-specific implementation for spoiled
+    gradient echo acquisition.
+    It is commonly used for rapid anatomical imaging and also for many different
+    qMRI applications.
+    When used for a single file, it does not convey any information about the
+    image contrast.
+    When used in a file collection, it may result in conflicts across filenames of
+    different applications.
+    **Change:** Removed from suffixes.
+IRT1:
+  name: Inversion recovery T1 mapping
+  description: |
+    The IRT1 method involves multiple inversion recovery spin-echo images
+    acquired at different inversion times
+    ([Barral et al. 2010](https://doi.org/10.1002/mrm.22497)).
+M0map:
+  name: Equilibrium magnetization (M0) map
+  description: |
+    In arbitrary units (arbitrary).
+    A common quantitative MRI (qMRI) fitting variable that represents the amount
+    of magnetization at thermal equilibrium.
+    M0 maps are RECOMMENDED to use this suffix if generated by qMRI applications
+    (for example, variable flip angle T1 mapping).
+  unit: arbitrary
+MEGRE:
+  name: Multi-echo Gradient Recalled Echo
+  description: |
+    Anatomical gradient echo images acquired at different echo times.
+    Please note that this suffix is not intended for the logical grouping of
+    images acquired using an Echo Planar Imaging (EPI) readout.
+MESE:
+  name: Multi-echo Spin Echo
+  description: |
+    The MESE method involves multiple spin echo images acquired at different echo
+    times and is primarily used for T2 mapping.
+    Please note that this suffix is not intended for the logical grouping of
+    images acquired using an Echo Planar Imaging (EPI) readout.
+MP2RAGE:
+  name: Magnetization Prepared Two Gradient Echoes
+  description: |
+    The MP2RAGE method is a special protocol that collects several images at
+    different flip angles and inversion times to create a parametric T1map by
+    combining the magnitude and phase images
+    ([Marques et al. 2010](https://doi.org/10.1016/j.neuroimage.2009.10.002)).
+MPM:
+  name: Multi-parametric Mapping
+  description: |
+    The MPM approaches (a.k.a hMRI) involves the acquisition of highly-similar
+    anatomical images that differ in terms of application of a magnetization
+    transfer RF pulse (MTon or MToff), flip angle and (optionally) echo time and
+    magnitue/phase parts
+    ([Weiskopf et al. 2013](https://doi.org/10.3389/fnins.2013.00095)).
+    See [here](https://owncloud.gwdg.de/index.php/s/iv2TOQwGy4FGDDZ) for
+    suggested MPM acquisition protocols.
+MTR:
+  name: Magnetization Transfer Ratio
+  description: |
+    This method is to calculate a semi-quantitative magnetization transfer ratio
+    map.
+MTRmap:
+  name: Magnetization transfer ratio image
+  description: |
+    In arbitrary units (arbitrary).
+    MTR maps are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+    MTRmap intensity values are RECOMMENDED to be represented in percentage in
+    the range of 0-100%.
+  unit: arbitrary
+  minValue: 0
+  maxValue: 100
+MTS:
+  name: Magnetization transfer saturation
+  description: |
+    This method is to calculate a semi-quantitative magnetization transfer
+    saturation index map.
+    The MTS method involves three sets of anatomical images that differ in terms
+    of application of a magnetization transfer RF pulse (MTon or MToff) and flip
+    angle ([Helms et al. 2008](https://doi.org/10.1002/mrm.21732)).
+MTVmap:
+  name: Macromolecular tissue volume (MTV) image
+  description: |
+    In arbitrary units (arbitrary).
+    MTV maps are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+  unit: arbitrary
+MTsat:
+  name: Magnetization transfer saturation image
+  description: |
+    In arbitrary units (arbitrary).
+    MTsat maps are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+  unit: arbitrary
+MWFmap:
+  name: Myelin water fraction image
+  description: |
+    In arbitrary units (arbitrary).
+    MWF maps are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+    MWF intensity values are RECOMMENDED to be represented in percentage in the
+    range of 0-100%.
+  unit: arbitrary
+  minValue: 0
+  maxValue: 100
+PD:
+  name: Proton density image
+  description: |
+    Ambiguous, may refer to a parametric image or to a conventional image.
+    **Change:** Replaced by `PDw` or `PDmap`.
+  unit: arbitrary
+PDT2:
+  name: PD and T2 weighted image
+  description: |
+    In arbitrary units (arbitrary).
+    PDw and T2w images acquired using a dual echo FSE sequence through view
+    sharing process
+    ([Johnson et al. 1994](https://pubmed.ncbi.nlm.nih.gov/8010268/)).
+  unit: arbitrary
+PDT2map:
+  name: Combined PD/T2 image
+  description: |
+    In arbitrary units (arbitrary).
+    Combined PD/T2 maps are REQUIRED to use this suffix regardless of the method
+    used to generate them.
+  unit: arbitrary
+PDmap:
+  name: Proton density image
+  description: |
+    In arbitrary units (arbitrary).
+    PD maps are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+  unit: arbitrary
+PDw:
+  name: Proton density (PD) weighted image
+  description: |
+    In arbitrary units (arbitrary).
+    The contrast of these images is mainly determined by spatial variations in
+    the spin density (1H) of the imaged specimen.
+    In spin-echo sequences this contrast is achieved at short repetition and long
+    echo times.
+    In a gradient-echo acquisition, PD weighting dominates the contrast at long
+    repetition and short echo times, and at small flip angles.
+  unit: arbitrary
+R1map:
+  name: Longitudinal relaxation rate image
+  description: |
+    In seconds<sup>-1</sup> (1/s).
+    R1 maps (R1 = 1/T1) are REQUIRED to use this suffix regardless of the method
+    used to generate them.
+  unit: 1/s
+R2map:
+  name: True transverse relaxation rate image
+  description: |
+    In seconds<sup>-1</sup> (1/s).
+    R2 maps (R2 = 1/T2) are REQUIRED to use this suffix regardless of the method
+    used to generate them.
+  unit: 1/s
+R2starmap:
+  name: Observed transverse relaxation rate image
+  description: |
+    In seconds<sup>-1</sup> (1/s).
+    R2-star maps (R2star = 1/T2star) are REQUIRED to use this suffix regardless
+    of the method used to generate them.
+  unit: 1/s
+RB1COR:
+  name: RB1COR
+  description: |
+    Low resolution images acquired by the body coil
+    (in the gantry of the scanner) and the head coil using identical acquisition
+    parameters to generate a combined sensitivity map as described in
+    [Papp et al. (2016)](https://doi.org/10.1002/mrm.26058).
+RB1map:
+  name: RF receive sensitivity map
+  description: |
+    In arbitrary units (arbitrary).
+    Radio frequency (RF) receive (B1-) sensitivity maps are REQUIRED to use this
+    suffix regardless of the method used to generate them.
+    RB1map intensity values are RECOMMENDED to be represented as percent
+    multiplicative factors such that Amplitude<sub>effective</sub> =
+    B1-<sub>intensity</sub>\*Amplitude<sub>ideal</sub>.
+  unit: arbitrary
+S0map:
+  name: Observed signal amplitude (S0) image
+  description: |
+    In arbitrary units (arbitrary).
+    For a multi-echo (typically fMRI) sequence, S0 maps index the baseline signal
+    before exponential (T2-star) signal decay.
+    In other words: the exponential of the intercept for a linear decay model
+    across log-transformed echos. For more information, please see, for example,
+    [the tedana documentation](https://tedana.readthedocs.io/en/latest/\
+    approach.html#monoexponential-decay-model-fit).
+    S0 maps are RECOMMENDED to use this suffix if derived from an ME-FMRI dataset.
+T1map:
+  name: Longitudinal relaxation time image
+  description: |
+    In seconds (s).
+    T1 maps are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+    See [this interactive book on T1 mapping](https://qmrlab.org/t1_book/intro)
+    for further reading on T1-mapping.
+  unit: s
+T1rho:
+  name: T1 in rotating frame (T1 rho) image
+  description: |
+    In seconds (s).
+    T1-rho maps are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+  unit: s
+T1w:
+  name: T1-weighted image
+  description: |
+    In arbitrary units (arbitrary).
+    The contrast of these images is mainly determined by spatial variations in
+    the longitudinal relaxation time of the imaged specimen.
+    In spin-echo sequences this contrast is achieved at relatively short
+    repetition and echo times.
+    To achieve this weighting in gradient-echo images, again, short repetition
+    and echo times are selected; however, at relatively large flip angles.
+    Another common approach to increase T1 weighting in gradient-echo images is
+    to add an inversion preparation block to the beginning of the imaging
+    sequence (for example, `TurboFLASH` or `MP-RAGE`).
+  unit: arbitrary
+T2map:
+  name: True transverse relaxation time image
+  description: |
+    In seconds (s).
+    T2 maps are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+  unit: s
+T2star:
+  name: T2\* image
+  description: |
+    Ambiguous, may refer to a parametric image or to a conventional image.
+    **Change:** Replaced by `T2starw` or `T2starmap`.
+  anyOf:
+  - unit: arbitrary
+  - unit: s
+T2starmap:
+  name: Observed transverse relaxation time image
+  description: |
+    In seconds (s).
+    T2-star maps are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+  unit: s
+T2starw:
+  name: T2star weighted image
+  description: |
+    In arbitrary units (arbitrary).
+    The contrast of these images is mainly determined by spatial variations in
+    the (observed) transverse relaxation time of the imaged specimen.
+    In spin-echo sequences, this effect is negated as the excitation is followed
+    by an inversion pulse.
+    The contrast of gradient-echo images natively depends on T2-star effects.
+    However, for T2-star variation to dominate the image contrast,
+    gradient-echo acquisitions are carried out at long repetition and echo times,
+    and at small flip angles.
+  unit: arbitrary
+T2w:
+  name: T2-weighted image
+  description: |
+    In arbitrary units (arbitrary).
+    The contrast of these images is mainly determined by spatial variations in
+    the (true) transverse relaxation time of the imaged specimen.
+    In spin-echo sequences this contrast is achieved at relatively long
+    repetition and echo times.
+    Generally, gradient echo sequences are not the most suitable option for
+    achieving T2 weighting, as their contrast natively depends on T2-star rather
+    than on T2.
+  unit: arbitrary
+TB1AFI:
+  name: TB1AFI
+  description: |
+    This method ([Yarnykh 2007](https://doi.org/10.1002/mrm.21120))
+    calculates a B1<sup>+</sup> map from two images acquired at interleaved (two)
+    TRs with identical RF pulses using a steady-state sequence.
+TB1DAM:
+  name: TB1DAM
+  description: |
+    The double-angle B1<sup>+</sup> method
+    ([Insko and Bolinger 1993](https://doi.org/10.1006/jmra.1993.1133)) is based
+    on the calculation of the actual angles from signal ratios,
+    collected by two acquisitions at different nominal excitation flip angles.
+    Common sequence types for this application include spin echo and echo planar
+    imaging.
+TB1EPI:
+  name: TB1EPI
+  description: |
+    This B1<sup>+</sup> mapping method
+    ([Jiru and Klose 2006](https://doi.org/10.1002/mrm.21083)) is based on two
+    EPI readouts to acquire spin echo (SE) and stimulated echo (STE) images at
+    multiple flip angles in one sequence, used in the calculation of deviations
+    from the nominal flip angle.
+TB1RFM:
+  name: TB1RFM
+  description: |
+    The result of a Siemens `rf_map` product sequence.
+    This sequence produces two images.
+    The first image appears like an anatomical image and the second output is a
+    scaled flip angle map.
+TB1SRGE:
+  name: TB1SRGE
+  description: |
+    Saturation-prepared with 2 rapid gradient echoes (SA2RAGE) uses a ratio of
+    two saturation recovery images with different time delays,
+    and a simulated look-up table to estimate B1+
+    ([Eggenschwiler et al. 2011](https://doi.org/10.1002/mrm.23145)).
+    This sequence can also be used in conjunction with MP2RAGE T1 mapping to
+    iteratively improve B1+ and T1 map estimation
+    ([Marques & Gruetter 2013](https://doi.org/10.1371/journal.pone.0069294)).
+TB1TFL:
+  name: TB1TFL
+  description: |
+    The result of a Siemens `tfl_b1_map` product sequence.
+    This sequence produces two images.
+    The first image appears like an anatomical image and the second output is a
+    scaled flip angle map.
+TB1map:
+  name: RF transmit field image
+  description: |
+    In arbitrary units (arbitrary).
+    Radio frequency (RF) transmit (B1+) field maps are REQUIRED to use this
+    suffix regardless of the method used to generate them.
+    TB1map intensity values are RECOMMENDED to be represented as percent
+    multiplicative factors such that FlipAngle<sub>effective</sub> =
+    B1+<sub>intensity</sub>\*FlipAngle<sub>nominal</sub> .
+  unit: arbitrary
+UNIT1:
+  name: Homogeneous (flat) T1-weighted MP2RAGE image
+  description: |
+    In arbitrary units (arbitrary).
+    UNIT1 images are REQUIRED to use this suffix regardless of the method used to
+    generate them.
+    Note that although this image is T1-weighted, regions without MR signal will
+    contain white salt-and-pepper noise that most segmentation algorithms will
+    fail on.
+    Therefore, it is important to dissociate it from from `T1w`.
+    Please see [`MP2RAGE` specific notes](/99-appendices/11-qmri.html#unit1-images)
+    in the qMRI appendix for further information.
+VFA:
+  name: Variable flip angle
+  description: |
+    The VFA method involves at least two spoiled gradient echo (SPGR) of
+    steady-state free precession (SSFP) images acquired at different flip angles.
+    Depending on the provided metadata fields and the sequence type,
+    data may be eligible for DESPOT1, DESPOT2 and their variants
+    ([Deoni et al. 2005](https://doi.org/10.1002/mrm.20314)).
+angio:
+  name: Angiogram
+  description: |
+    Magnetic resonance angiography sequences focus on enhancing the contrast of
+    blood vessels (generally arteries, but sometimes veins) against other tissue
+    types.
+asl:
+  name: Arterial Spin Labeling
+  description: |
+    The complete ASL time series stored as a 4D NIfTI file in the original
+    acquisition order, with possible volume types including: control, label,
+    m0scan, deltam, cbf.
+aslcontext:
+  name: Arterial Spin Labeling Context
+  description: |
+    A TSV file defining the image types for volumes in an associated ASL file.
+asllabeling:
+  name: ASL Labeling Screenshot
+  description: |
+    An anonymized screenshot of the planning of the labeling slab/plane with
+    respect to the imaging slab or slices `*_asllabeling.jpg`.
+    Based on DICOM macro C.8.13.5.14.
+beh:
+  name: Behavioral recording
+  description: |
+    Behavioral recordings from tasks.
+    These files are similar to events files, but do not include the `"onset"` and
+    `"duration"` columns that are mandatory for events files.
+blood:
+  name: Blood recording data
+  description: |
+    Blood measurements of radioactivity stored in
+    [tabular files](/02-common-principles.html#tabular-files)
+    and located in the `pet/` directory along with the corresponding PET data.
+bold:
+  name: Blood-Oxygen-Level Dependent image
+  description: |
+    Blood-Oxygen-Level Dependent contrast (specialized T2\* weighting)
+cbv:
+  name: Cerebral blood volume image
+  description: |
+    Cerebral Blood Volume contrast (specialized T2\* weighting or difference between T1 weighted images)
+channels:
+  name: Channels File
+  description: |
+    Channel information.
+coordsystem:
+  name: Coordinate System File
+  description: |
+    A JSON document specifying the coordinate system(s) used for the MEG, EEG,
+    head localization coils, and anatomical landmarks.
+defacemask:
+  name: Defacing Mask
+  description: |
+    A binary mask that was used to remove facial features from an anatomical MRI
+    image.
+dwi:
+  name: Diffusion-weighted image
+  description: |
+    Diffusion-weighted imaging contrast (specialized T2\* weighting).
+eeg:
+  name: Electroencephalography
+  description: |
+    Electroencephalography recording data.
+electrodes:
+  name: Electrodes
+  description: |
+    File that gives the location of (i)EEG electrodes.
+epi:
+  name: EPI
+  description: |
+    The phase-encoding polarity (PEpolar) technique combines two or more Spin Echo
+    EPI scans with different phase encoding directions to estimate the underlying
+    inhomogeneity/deformation map.
+events:
+  name: Events
+  description: |
+    Event timing information from a behavioral task.
+fieldmap:
+  name: Fieldmap
+  description: |
+    Some MR schemes such as spiral-echo imaging (SEI) sequences are able to
+    directly provide maps of the *B<sub>0</sub>* field inhomogeneity.
+headshape:
+  name: Headshape File
+  description: |
+    The 3-D locations of points that describe the head shape and/or electrode
+    locations can be digitized and stored in separate files.
+ieeg:
+  name: Intracranial Electroencephalography
+  description: |
+    Intracranial electroencephalography recording data.
+inplaneT1:
+  name: Inplane T1
+  description: |
+    In arbitrary units (arbitrary).
+    T1 weighted structural image matched to a functional (task) image.
+  unit: arbitrary
+inplaneT2:
+  name: Inplane T2
+  description: |
+    In arbitrary units (arbitrary).
+    T2 weighted structural image matched to a functional (task) image.
+  unit: arbitrary
+m0scan:
+  name: M0 image
+  description: |
+    The M0 image is a calibration image, used to estimate the equilibrium
+    magnetization of blood.
+magnitude:
+  name: Magnitude
+  description: |
+    Field-mapping MR schemes such as gradient-recalled echo (GRE) generate a
+    Magnitude image to be used for anatomical reference.
+    Requires the existence of Phase, Phase-difference or Fieldmap maps.
+magnitude1:
+  name: Magnitude
+  description: |
+    Magnitude map generated by GRE or similar schemes, associated with the first
+    echo in the sequence.
+magnitude2:
+  name: Magnitude
+  description: |
+    Magnitude map generated by GRE or similar schemes, associated with the second
+    echo in the sequence.
+markers:
+  name: MEG Sensor Coil Positions
+  description: |
+    Another manufacturer-specific detail pertains to the KIT/Yokogawa/Ricoh
+    system, which saves the MEG sensor coil positions in a separate file with two
+    possible filename extensions  (`.sqd`, `.mrk`).
+    For these files, the `markers` suffix MUST be used.
+    For example: `sub-01_task-nback_markers.sqd`
+meg:
+  name: Magnetoencephalography
+  description: |
+    Unprocessed MEG data stored in the native file format of the MEG instrument
+    with which the data was collected.
+pet:
+  name: Positron Emission Tomography
+  description: |
+    PET imaging data SHOULD be stored in 4D
+    (or 3D, if only one volume was acquired) NIfTI files with the `_pet` suffix.
+    Volumes MUST be stored in chronological order
+    (the order they were acquired in).
+phase:
+  name: Phase image
+  description: |
+    [DEPRECATED](/02-common-principles.html#definitions).
+    Phase information associated with magnitude information stored in BOLD
+    contrast.
+    This suffix should be replaced by the
+    [`part-phase`](/99-appendices/09-entities.html#part)
+    in conjunction with the `bold` suffix.
+  anyOf:
+  - unit: arbitrary
+  - unit: rad
+phase1:
+  name: Phase
+  description: |
+    Phase map generated by GRE or similar schemes, associated with the first
+    echo in the sequence.
+phase2:
+  name: Phase
+  description: |
+    Phase map generated by GRE or similar schemes, associated with the second
+    echo in the sequence.
+phasediff:
+  name: Phase-difference
+  description: |
+    Some scanners subtract the `phase1` from the `phase2` map and generate a
+    unique `phasediff` file.
+    For instance, this is a common output for the built-in fieldmap sequence of
+    Siemens scanners.
+photo:
+  name: Photo File
+  description: |
+    Photos of the anatomical landmarks and/or head localization coils
+    (`*_photo.jpg`).
+physio:
+  name: Physiological recording
+  description: |
+    Physiological recordings such as cardiac and respiratory signals.
+sbref:
+  name: Single-band reference image
+  description: |
+    Single-band reference for one or more multi-band `dwi` images.
+stim:
+  name: Continuous recording
+  description: |
+    Continuous measures, such as parameters of a film or audio stimulus.
diff --git a/src/schema/objects/top_level_files.yaml b/src/schema/objects/top_level_files.yaml
new file mode 100644
index 0000000000..12e1823472
--- /dev/null
+++ b/src/schema/objects/top_level_files.yaml
@@ -0,0 +1,79 @@
+---
+# This file describes files which may appear at the top level of a dataset.
+# This does not include information about whether these files are required or optional.
+# For that information, see `rules/top_level_files.yaml`.
+CHANGES:
+  name: CHANGES
+  description: |
+    Version history of the dataset (describing changes, updates and corrections) MAY be provided in
+    the form of a `CHANGES` text file.
+    This file MUST follow the
+    [CPAN Changelog convention](https://metacpan.org/pod/release/HAARG/CPAN-Changes-0.400002/lib/\
+    CPAN/Changes/Spec.pod).
+    The `CHANGES` file MUST be either in ASCII or UTF-8 encoding.
+LICENSE:
+  name: LICENSE
+  description: |
+    A `LICENSE` file MAY be provided in addition to the short specification of the
+    used license in the `dataset_description.json` `"License"` field.
+    The `"License"` field and `LICENSE` file MUST correspond.
+    The `LICENSE` file MUST be either in ASCII or UTF-8 encoding.
+README:
+  name: README
+  description: |
+    In addition a free form text file (`README`) describing the dataset in more details SHOULD be
+    provided.
+    The `README` file MUST be either in ASCII or UTF-8 encoding.
+dataset_description:
+  name: Dataset Description
+  description: |
+    The file `dataset_description.json` is a JSON file describing the dataset.
+genetic_info:
+  name: Genetic Information
+  description: |
+    The `genetic_info.json` file describes the genetic information available in the
+    `participants.tsv` file and/or the genetic database described in
+    `dataset_description.json`.
+    Datasets containing the `Genetics` field in `dataset_description.json` or the
+    `genetic_id` column in `participants.tsv` MUST include this file.
+participants:
+  name: Participant Information
+  description: |
+    The purpose of this RECOMMENDED file is to describe properties of participants
+    such as age, sex, handedness.
+    If this file exists, it MUST contain the column `participant_id`,
+    which MUST consist of `sub-<label>` values identifying one row for each participant,
+    followed by a list of optional columns describing participants.
+    Each participant MUST be described by one and only one row.
+
+    Commonly used *optional* columns in `participant.tsv` files are `age`, `sex`,
+    and `handedness`. We RECOMMEND to make use of these columns, and
+    in case that you do use them, we RECOMMEND to use the following values
+    for them:
+
+    -   `age`: numeric value in years (float or integer value)
+
+    -   `sex`: string value indicating phenotypical sex, one of "male", "female",
+        "other"
+
+        -   for "male", use one of these values: `male`, `m`, `M`, `MALE`, `Male`
+
+        -   for "female", use one of these values: `female`, `f`, `F`, `FEMALE`,
+            `Female`
+
+        -   for "other", use one of these values: `other`, `o`, `O`, `OTHER`,
+            `Other`
+
+    -   `handedness`: string value indicating one of "left", "right",
+        "ambidextrous"
+
+        -   for "left", use one of these values: `left`, `l`, `L`, `LEFT`, `Left`
+
+        -   for "right", use one of these values: `right`, `r`, `R`, `RIGHT`,
+            `Right`
+
+        -   for "ambidextrous", use one of these values: `ambidextrous`, `a`, `A`,
+            `AMBIDEXTROUS`, `Ambidextrous`
+
+    Throughout BIDS you can indicate missing values with `n/a` (for "not
+    available").
diff --git a/src/schema/rules/associated_data.yaml b/src/schema/rules/associated_data.yaml
new file mode 100644
index 0000000000..609fcafaa5
--- /dev/null
+++ b/src/schema/rules/associated_data.yaml
@@ -0,0 +1,11 @@
+---
+# This file describes the requirement levels of folders which may appear
+# within a dataset folder without following BIDS format.
+code:
+  required: false
+derivatives:
+  required: false
+sourcedata:
+  required: false
+stimuli:
+  required: false
diff --git a/src/schema/datatypes/anat.yaml b/src/schema/rules/datatypes/anat.yaml
similarity index 71%
rename from src/schema/datatypes/anat.yaml
rename to src/schema/rules/datatypes/anat.yaml
index 5ae49feda3..82d99b44b9 100644
--- a/src/schema/datatypes/anat.yaml
+++ b/src/schema/rules/datatypes/anat.yaml
@@ -1,22 +1,22 @@
 ---
 # Nonparametric
 - suffixes:
-    - T1w
-    - T2w
-    - PDw
-    - T2starw
-    - FLAIR
-    - inplaneT1
-    - inplaneT2
-    - PDT2
-    - angio
-    - T2star  # deprecated
-    - FLASH  # deprecated
-    - PD  # deprecated
+  - T1w
+  - T2w
+  - PDw
+  - T2starw
+  - FLAIR
+  - inplaneT1
+  - inplaneT2
+  - PDT2
+  - angio
+  - T2star  # deprecated
+  - FLASH  # deprecated
+  - PD  # deprecated
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -25,29 +25,30 @@
     ceagent: optional
     reconstruction: optional
     part: optional
+
 # Parametric
 - suffixes:
-    - T1map
-    - T2map
-    - T2starmap
-    - R1map
-    - R2map
-    - R2starmap
-    - PDmap
-    - MTRmap
-    - MTsat
-    - UNIT1
-    - T1rho
-    - MWFmap
-    - MTVmap
-    - PDT2map
-    - Chimap
-    - S0map
-    - M0map
+  - T1map
+  - T2map
+  - T2starmap
+  - R1map
+  - R2map
+  - R2starmap
+  - PDmap
+  - MTRmap
+  - MTsat
+  - UNIT1
+  - T1rho
+  - MWFmap
+  - MTVmap
+  - PDT2map
+  - Chimap
+  - S0map
+  - M0map
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -55,13 +56,14 @@
     acquisition: optional
     ceagent: optional
     reconstruction: optional
+
 # Defacemask
 - suffixes:
-    - defacemask
+  - defacemask
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -70,14 +72,15 @@
     ceagent: optional
     reconstruction: optional
     modality: optional
+
 # Multi-echo
 - suffixes:
-    - MESE
-    - MEGRE
+  - MESE
+  - MEGRE
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -87,13 +90,14 @@
     reconstruction: optional
     echo: required
     part: optional
+
 # Multi-flip
 - suffixes:
-    - VFA
+  - VFA
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -103,13 +107,14 @@
     reconstruction: optional
     flip: required
     part: optional
+
 # Multi-inv
 - suffixes:
-    - IRT1
+  - IRT1
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -119,13 +124,14 @@
     reconstruction: optional
     inversion: required
     part: optional
+
 # MP2RAGE
 - suffixes:
-    - MP2RAGE
+  - MP2RAGE
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -137,14 +143,15 @@
     flip: optional
     inversion: required
     part: optional
+
 # VFA+MT
 - suffixes:
-    - MPM
-    - MTS
+  - MPM
+  - MTS
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -156,13 +163,14 @@
     flip: required
     mtransfer: required
     part: optional
+
 # MTR
 - suffixes:
-    - MTR
+  - MTR
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
diff --git a/src/schema/datatypes/beh.yaml b/src/schema/rules/datatypes/beh.yaml
similarity index 71%
rename from src/schema/datatypes/beh.yaml
rename to src/schema/rules/datatypes/beh.yaml
index d9de3cd0d0..59358b59ba 100644
--- a/src/schema/datatypes/beh.yaml
+++ b/src/schema/rules/datatypes/beh.yaml
@@ -1,11 +1,11 @@
 ---
-# First group
+# Continuous data
 - suffixes:
-    - stim
-    - physio
+  - stim
+  - physio
   extensions:
-    - .tsv.gz
-    - .json
+  - .tsv.gz
+  - .json
   entities:
     subject: required
     session: optional
@@ -13,13 +13,14 @@
     acquisition: optional
     run: optional
     recording: optional
-# Second group
+
+# Non-continuous data
 - suffixes:
-    - events
-    - beh
+  - events
+  - beh
   extensions:
-    - .tsv
-    - .json
+  - .tsv
+  - .json
   entities:
     subject: required
     session: optional
diff --git a/src/schema/datatypes/dwi.yaml b/src/schema/rules/datatypes/dwi.yaml
similarity index 75%
rename from src/schema/datatypes/dwi.yaml
rename to src/schema/rules/datatypes/dwi.yaml
index 561ca1a5a2..b867d3dc6e 100644
--- a/src/schema/datatypes/dwi.yaml
+++ b/src/schema/rules/datatypes/dwi.yaml
@@ -1,13 +1,13 @@
 ---
 # DWI
 - suffixes:
-    - dwi
+  - dwi
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
-    - .bvec
-    - .bval
+  - .nii.gz
+  - .nii
+  - .json
+  - .bvec
+  - .bval
   entities:
     subject: required
     session: optional
@@ -15,13 +15,14 @@
     direction: optional
     run: optional
     part: optional
+
 # Single-band reference images
 - suffixes:
-    - sbref
+  - sbref
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
diff --git a/src/schema/datatypes/eeg.yaml b/src/schema/rules/datatypes/eeg.yaml
similarity index 74%
rename from src/schema/datatypes/eeg.yaml
rename to src/schema/rules/datatypes/eeg.yaml
index bad4b9f04d..5951137af6 100644
--- a/src/schema/datatypes/eeg.yaml
+++ b/src/schema/rules/datatypes/eeg.yaml
@@ -1,66 +1,71 @@
 ---
 - suffixes:
-    - eeg
+  - eeg
   extensions:
-    - .json
-    - .edf
-    - .vhdr
-    - .vmrk
-    - .eeg
-    - .set
-    - .fdt
-    - .bdf
+  - .json
+  - .edf
+  - .vhdr
+  - .vmrk
+  - .eeg
+  - .set
+  - .fdt
+  - .bdf
   entities:
     subject: required
     session: optional
     task: required
     acquisition: optional
     run: optional
+
 - suffixes:
-    - channels
+  - channels
   extensions:
-    - .json
-    - .tsv
+  - .json
+  - .tsv
   entities:
     subject: required
     session: optional
     task: required
     acquisition: optional
     run: optional
+
 - suffixes:
-    - coordsystem
+  - coordsystem
   extensions:
-    - .json
+  - .json
   entities:
     subject: required
     session: optional
     acquisition: optional
     space: optional
+
 - suffixes:
-    - electrodes
+  - electrodes
   extensions:
-    - .json
-    - .tsv
+  - .json
+  - .tsv
   entities:
     subject: required
     session: optional
     acquisition: optional
     space: optional
+
 - suffixes:
-    - events
+  - events
   extensions:
-    - .json
-    - .tsv
+  - .json
+  - .tsv
   entities:
     subject: required
     session: optional
     task: required
     acquisition: optional
     run: optional
+
 - suffixes:
-    - photo
+  - photo
   extensions:
-    - .jpg
+  - .jpg
   entities:
     subject: required
     session: optional
diff --git a/src/schema/datatypes/fmap.yaml b/src/schema/rules/datatypes/fmap.yaml
similarity index 75%
rename from src/schema/datatypes/fmap.yaml
rename to src/schema/rules/datatypes/fmap.yaml
index 6192757a5d..2c445196d6 100644
--- a/src/schema/datatypes/fmap.yaml
+++ b/src/schema/rules/datatypes/fmap.yaml
@@ -1,30 +1,31 @@
 ---
 # Fieldmaps
 - suffixes:
-    - phasediff
-    - phase1
-    - phase2
-    - magnitude1
-    - magnitude2
-    - magnitude
-    - fieldmap
+  - phasediff
+  - phase1
+  - phase2
+  - magnitude1
+  - magnitude2
+  - magnitude
+  - fieldmap
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
     acquisition: optional
     run: optional
+
 # PEPolar
 - suffixes:
-    - epi
-    - m0scan
+  - epi
+  - m0scan
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -32,13 +33,14 @@
     ceagent: optional
     direction: required
     run: optional
+
 # TB1DAM
 - suffixes:
-    - TB1DAM
+  - TB1DAM
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -49,13 +51,14 @@
     flip: required
     inversion: optional
     part: optional
+
 # TB1EPI
 - suffixes:
-    - TB1EPI
+  - TB1EPI
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -67,16 +70,17 @@
     flip: required
     inversion: optional
     part: optional
+
 # RFFieldMaps
 - suffixes:
-    - TB1AFI
-    - TB1TFL
-    - TB1RFM
-    - RB1COR
+  - TB1AFI
+  - TB1TFL
+  - TB1RFM
+  - RB1COR
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -88,13 +92,14 @@
     flip: optional
     inversion: optional
     part: optional
+
 # TB1SRGE
 - suffixes:
-    - TB1SRGE
+  - TB1SRGE
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -106,14 +111,15 @@
     flip: required
     inversion: required
     part: optional
+
 # Parametric
 - suffixes:
-    - TB1map
-    - RB1map
+  - TB1map
+  - RB1map
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
diff --git a/src/schema/datatypes/func.yaml b/src/schema/rules/datatypes/func.yaml
similarity index 82%
rename from src/schema/datatypes/func.yaml
rename to src/schema/rules/datatypes/func.yaml
index ce0ec7a334..1fbdca7b53 100644
--- a/src/schema/datatypes/func.yaml
+++ b/src/schema/rules/datatypes/func.yaml
@@ -1,13 +1,13 @@
 ---
 # Func
 - suffixes:
-    - bold
-    - cbv
-    - sbref
+  - bold
+  - cbv
+  - sbref
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -19,13 +19,14 @@
     run: optional
     echo: optional
     part: optional
+
 # Phase (deprecated)
 - suffixes:
-    - phase  # deprecated
+  - phase  # deprecated
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -36,12 +37,13 @@
     direction: optional
     run: optional
     echo: optional
+
 # Events
 - suffixes:
-    - events
+  - events
   extensions:
-    - .tsv
-    - .json
+  - .tsv
+  - .json
   entities:
     subject: required
     session: optional
@@ -51,13 +53,14 @@
     reconstruction: optional
     direction: optional
     run: optional
+
 # Timeseries
 - suffixes:
-    - physio
-    - stim
+  - physio
+  - stim
   extensions:
-    - .tsv.gz
-    - .json
+  - .tsv.gz
+  - .json
   entities:
     subject: required
     session: optional
diff --git a/src/schema/datatypes/ieeg.yaml b/src/schema/rules/datatypes/ieeg.yaml
similarity index 74%
rename from src/schema/datatypes/ieeg.yaml
rename to src/schema/rules/datatypes/ieeg.yaml
index 612440b080..2b393cda54 100644
--- a/src/schema/datatypes/ieeg.yaml
+++ b/src/schema/rules/datatypes/ieeg.yaml
@@ -1,67 +1,72 @@
 ---
 - suffixes:
-    - ieeg
+  - ieeg
   extensions:
-    - .mefd/
-    - .json
-    - .edf
-    - .vhdr
-    - .eeg
-    - .vmrk
-    - .set
-    - .fdt
-    - .nwb
+  - .mefd/
+  - .json
+  - .edf
+  - .vhdr
+  - .eeg
+  - .vmrk
+  - .set
+  - .fdt
+  - .nwb
   entities:
     subject: required
     session: optional
     task: required
     acquisition: optional
     run: optional
+
 - suffixes:
-    - channels
+  - channels
   extensions:
-    - .json
-    - .tsv
+  - .json
+  - .tsv
   entities:
     subject: required
     session: optional
     task: required
     acquisition: optional
     run: optional
+
 - suffixes:
-    - coordsystem
+  - coordsystem
   extensions:
-    - .json
+  - .json
   entities:
     subject: required
     session: optional
     acquisition: optional
     space: optional
+
 - suffixes:
-    - electrodes
+  - electrodes
   extensions:
-    - .json
-    - .tsv
+  - .json
+  - .tsv
   entities:
     subject: required
     session: optional
     acquisition: optional
     space: optional
+
 - suffixes:
-    - events
+  - events
   extensions:
-    - .json
-    - .tsv
+  - .json
+  - .tsv
   entities:
     subject: required
     session: optional
     task: required
     acquisition: optional
     run: optional
+
 - suffixes:
-    - photo
+  - photo
   extensions:
-    - .jpg
+  - .jpg
   entities:
     subject: required
     session: optional
diff --git a/src/schema/datatypes/meg.yaml b/src/schema/rules/datatypes/meg.yaml
similarity index 74%
rename from src/schema/datatypes/meg.yaml
rename to src/schema/rules/datatypes/meg.yaml
index b2c1e3e8ef..132a0b81e9 100644
--- a/src/schema/datatypes/meg.yaml
+++ b/src/schema/rules/datatypes/meg.yaml
@@ -1,19 +1,19 @@
 ---
 # First group
 - suffixes:
-    - meg
+  - meg
   extensions:
-    - /  # corresponds to BTi/4D data
-    - .ds/
-    - .json
-    - .fif
-    - .sqd
-    - .con
-    - .raw
-    - .ave
-    - .mrk
-    - .kdf
-    - .mhd
+  - /  # corresponds to BTi/4D data
+  - .ds/
+  - .json
+  - .fif
+  - .sqd
+  - .con
+  - .raw
+  - .ave
+  - .mrk
+  - .kdf
+  - .mhd
   entities:
     subject: required
     session: optional
@@ -22,41 +22,45 @@
     run: optional
     processing: optional
     split: optional
+
 # Second group
 - suffixes:
-    - headshape
+  - headshape
   extensions:
-    - "*"
+  - "*"
   entities:
     subject: required
     session: optional
     acquisition: optional
+
 # Third group
 - suffixes:
-    - markers
+  - markers
   extensions:
-    - .sqd
-    - .mrk
+  - .sqd
+  - .mrk
   entities:
     subject: required
     session: optional
     task: optional
     acquisition: optional
     space: optional
+
 # Fourth
 - suffixes:
-    - coordsystem
+  - coordsystem
   extensions:
-    - .json
+  - .json
   entities:
     subject: required
     session: optional
     acquisition: optional
+
 - suffixes:
-    - channels
+  - channels
   extensions:
-    - .json
-    - .tsv
+  - .json
+  - .tsv
   entities:
     subject: required
     session: optional
@@ -64,21 +68,23 @@
     acquisition: optional
     run: optional
     processing: optional
+
 - suffixes:
-    - events
+  - events
   extensions:
-    - .json
-    - .tsv
+  - .json
+  - .tsv
   entities:
     subject: required
     session: optional
     task: required
     acquisition: optional
     run: optional
+
 - suffixes:
-    - photo
+  - photo
   extensions:
-    - .jpg
+  - .jpg
   entities:
     subject: required
     session: optional
diff --git a/src/schema/datatypes/perf.yaml b/src/schema/rules/datatypes/perf.yaml
similarity index 81%
rename from src/schema/datatypes/perf.yaml
rename to src/schema/rules/datatypes/perf.yaml
index be65420714..4db73d61ca 100644
--- a/src/schema/datatypes/perf.yaml
+++ b/src/schema/rules/datatypes/perf.yaml
@@ -1,12 +1,12 @@
 ---
 # First group
 - suffixes:
-    - asl
-    - m0scan
+  - asl
+  - m0scan
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -14,12 +14,13 @@
     reconstruction: optional
     direction: optional
     run: optional
+
 # Second group
 - suffixes:
-    - aslcontext
+  - aslcontext
   extensions:
-    - .tsv
-    - .json
+  - .tsv
+  - .json
   entities:
     subject: required
     session: optional
@@ -27,11 +28,12 @@
     reconstruction: optional
     direction: optional
     run: optional
+
 # Third group
 - suffixes:
-    - asllabeling
+  - asllabeling
   extensions:
-    - .jpg
+  - .jpg
   entities:
     subject: required
     session: optional
diff --git a/src/schema/datatypes/pet.yaml b/src/schema/rules/datatypes/pet.yaml
similarity index 83%
rename from src/schema/datatypes/pet.yaml
rename to src/schema/rules/datatypes/pet.yaml
index b5fa387b70..1faed9482a 100644
--- a/src/schema/datatypes/pet.yaml
+++ b/src/schema/rules/datatypes/pet.yaml
@@ -1,11 +1,11 @@
 ---
 # PET recordings
 - suffixes:
-    - pet
+  - pet
   extensions:
-    - .nii.gz
-    - .nii
-    - .json
+  - .nii.gz
+  - .nii
+  - .json
   entities:
     subject: required
     session: optional
@@ -13,12 +13,13 @@
     tracer: optional
     reconstruction: optional
     run: optional
+
 # Blood recordings
 - suffixes:
-    - blood
+  - blood
   extensions:
-    - .tsv
-    - .json
+  - .tsv
+  - .json
   entities:
     subject: required
     session: optional
@@ -27,12 +28,13 @@
     reconstruction: optional
     run: optional
     recording: required
+
 # Events
 - suffixes:
-    - events
+  - events
   extensions:
-    - .tsv
-    - .json
+  - .tsv
+  - .json
   entities:
     subject: required
     session: optional
diff --git a/src/schema/rules/entities.yaml b/src/schema/rules/entities.yaml
new file mode 100644
index 0000000000..c36b591b72
--- /dev/null
+++ b/src/schema/rules/entities.yaml
@@ -0,0 +1,27 @@
+---
+# This file simply defines the order in which entities should appear within filenames.
+# Entity definitions appear in the `objects/entities.yaml` file.
+- subject
+- session
+- sample
+- task
+- acquisition
+- ceagent
+- tracer
+- reconstruction
+- direction
+- run
+- modality
+- echo
+- flip
+- inversion
+- mtransfer
+- part
+- recording
+- processing
+- space
+- split
+- resolution
+- density
+- label
+- description
diff --git a/src/schema/rules/modalities.yaml b/src/schema/rules/modalities.yaml
new file mode 100644
index 0000000000..9127db93e7
--- /dev/null
+++ b/src/schema/rules/modalities.yaml
@@ -0,0 +1,24 @@
+---
+# This file defines which data types fall under each modality.
+mri:
+  datatypes:
+  - anat
+  - dwi
+  - fmap
+  - func
+  - perf
+eeg:
+  datatypes:
+  - eeg
+ieeg:
+  datatypes:
+  - ieeg
+meg:
+  datatypes:
+  - meg
+beh:
+  datatypes:
+  - beh
+pet:
+  datatypes:
+  - pet
diff --git a/src/schema/top_level_files.yaml b/src/schema/rules/top_level_files.yaml
similarity index 75%
rename from src/schema/top_level_files.yaml
rename to src/schema/rules/top_level_files.yaml
index 98a74a12b6..f24133deba 100644
--- a/src/schema/top_level_files.yaml
+++ b/src/schema/rules/top_level_files.yaml
@@ -2,30 +2,30 @@
 README:
   required: true
   extensions:
-    - None
+  - None
 CHANGES:
   required: true
   extensions:
-    - None
+  - None
 LICENSE:
   required: false
   extensions:
-    - None
+  - None
 dataset_description:
   required: true
   extensions:
-    - .json
+  - .json
 genetic_info:
   required: false
   extensions:
-    - .json
+  - .json
 participants:
   required: false
   extensions:
-    - .tsv
-    - .json
+  - .tsv
+  - .json
 samples:
   required: false
   extensions:
-    - .tsv
-    - .json
+  - .tsv
+  - .json
diff --git a/src/schema/suffixes/Chimap.yaml b/src/schema/suffixes/Chimap.yaml
deleted file mode 100644
index d5c1463da7..0000000000
--- a/src/schema/suffixes/Chimap.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: Quantitative susceptibility map (QSM)
-description: |
-  In parts per million (ppm).
-  QSM allows for determining the underlying magnetic susceptibility of tissue
-  (Chi)
-  ([Wang & Liu, 2014](https://onlinelibrary.wiley.com/doi/10.1002/mrm.25358)).
-  Chi maps are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-unit: ppm
diff --git a/src/schema/suffixes/FLAIR.yaml b/src/schema/suffixes/FLAIR.yaml
deleted file mode 100644
index 15a5d177a8..0000000000
--- a/src/schema/suffixes/FLAIR.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: Fluid attenuated inversion recovery image
-description: |
-  In arbitrary units (arbitrary).
-  Structural images with predominant T2 contribution (also known as T2-FLAIR),
-  in which signal from fluids (for example, CSF) is nulled out by adjusting
-  inversion time, coupled with notably long repetition and echo times.
-unit: arbitrary
diff --git a/src/schema/suffixes/FLASH.yaml b/src/schema/suffixes/FLASH.yaml
deleted file mode 100644
index 5e8f678a53..0000000000
--- a/src/schema/suffixes/FLASH.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: Fast-Low-Angle-Shot image
-description: |
-  FLASH (Fast-Low-Angle-Shot) is a vendor-specific implementation for spoiled
-  gradient echo acquisition.
-  It is commonly used for rapid anatomical imaging and also for many different
-  qMRI applications.
-  When used for a single file, it does not convey any information about the
-  image contrast.
-  When used in a file collection, it may result in conflicts across filenames of
-  different applications.
-  **Change:** Removed from suffixes.
diff --git a/src/schema/suffixes/IRT1.yaml b/src/schema/suffixes/IRT1.yaml
deleted file mode 100644
index 0c362a5ee4..0000000000
--- a/src/schema/suffixes/IRT1.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Inversion recovery T1 mapping
-description: |
-  The IRT1 method involves multiple inversion recovery spin-echo images
-  acquired at different inversion times
-  ([Barral et al. 2010](https://doi.org/10.1002/mrm.22497)).
diff --git a/src/schema/suffixes/M0map.yaml b/src/schema/suffixes/M0map.yaml
deleted file mode 100644
index 32449df3cd..0000000000
--- a/src/schema/suffixes/M0map.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: Equilibrium magnetization (M0) map
-description: |
-  In arbitrary units (arbitrary).
-  A common quantitative MRI (qMRI) fitting variable that represents the amount
-  of magnetization at thermal equilibrium.
-  M0 maps are RECOMMENDED to use this suffix if generated by qMRI applications
-  (for example, variable flip angle T1 mapping).
-unit: arbitrary
diff --git a/src/schema/suffixes/MEGRE.yaml b/src/schema/suffixes/MEGRE.yaml
deleted file mode 100644
index c30fa512cc..0000000000
--- a/src/schema/suffixes/MEGRE.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Multi-echo Gradient Recalled Echo
-description: |
-  Anatomical gradient echo images acquired at different echo times.
-  Please note that this suffix is not intended for the logical grouping of
-  images acquired using an Echo Planar Imaging (EPI) readout.
diff --git a/src/schema/suffixes/MESE.yaml b/src/schema/suffixes/MESE.yaml
deleted file mode 100644
index b9633cf763..0000000000
--- a/src/schema/suffixes/MESE.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Multi-echo Spin Echo
-description: |
-  The MESE method involves multiple spin echo images acquired at different echo
-  times and is primarily used for T2 mapping.
-  Please note that this suffix is not intended for the logical grouping of
-  images acquired using an Echo Planar Imaging (EPI) readout.
diff --git a/src/schema/suffixes/MP2RAGE.yaml b/src/schema/suffixes/MP2RAGE.yaml
deleted file mode 100644
index ab98964bc0..0000000000
--- a/src/schema/suffixes/MP2RAGE.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Magnetization Prepared Two Gradient Echoes
-description: |
-  The MP2RAGE method is a special protocol that collects several images at
-  different flip angles and inversion times to create a parametric T1map by
-  combining the magnitude and phase images
-  ([Marques et al. 2010](https://doi.org/10.1016/j.neuroimage.2009.10.002)).
diff --git a/src/schema/suffixes/MPM.yaml b/src/schema/suffixes/MPM.yaml
deleted file mode 100644
index a536ff06ca..0000000000
--- a/src/schema/suffixes/MPM.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: Multi-parametric Mapping
-description: |
-  The MPM approaches (a.k.a hMRI) involves the acquisition of highly-similar
-  anatomical images that differ in terms of application of a magnetization
-  transfer RF pulse (MTon or MToff), flip angle and (optionally) echo time and
-  magnitue/phase parts
-  ([Weiskopf et al. 2013](https://doi.org/10.3389/fnins.2013.00095)).
-  See [here](https://owncloud.gwdg.de/index.php/s/iv2TOQwGy4FGDDZ) for
-  suggested MPM acquisition protocols.
diff --git a/src/schema/suffixes/MTR.yaml b/src/schema/suffixes/MTR.yaml
deleted file mode 100644
index 47a8946ce0..0000000000
--- a/src/schema/suffixes/MTR.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Magnetization Transfer Ratio
-description: |
-  This method is to calculate a semi-quantitative magnetization transfer ratio
-  map.
diff --git a/src/schema/suffixes/MTRmap.yaml b/src/schema/suffixes/MTRmap.yaml
deleted file mode 100644
index 654df49e78..0000000000
--- a/src/schema/suffixes/MTRmap.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: Magnetization transfer ratio image
-description: |
-  In arbitrary units (arbitrary).
-  MTR maps are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-  MTRmap intensity values are RECOMMENDED to be represented in percentage in
-  the range of 0-100%.
-unit: arbitrary
-minValue: 0
-maxValue: 100
diff --git a/src/schema/suffixes/MTS.yaml b/src/schema/suffixes/MTS.yaml
deleted file mode 100644
index f2417db654..0000000000
--- a/src/schema/suffixes/MTS.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: Magnetization transfer saturation
-description: |
-  This method is to calculate a semi-quantitative magnetization transfer
-  saturation index map.
-  The MTS method involves three sets of anatomical images that differ in terms
-  of application of a magnetization transfer RF pulse (MTon or MToff) and flip
-  angle ([Helms et al. 2008](https://doi.org/10.1002/mrm.21732)).
diff --git a/src/schema/suffixes/MTVmap.yaml b/src/schema/suffixes/MTVmap.yaml
deleted file mode 100644
index 524dc29fc9..0000000000
--- a/src/schema/suffixes/MTVmap.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Macromolecular tissue volume (MTV) image
-description: |
-  In arbitrary units (arbitrary).
-  MTV maps are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-unit: arbitrary
diff --git a/src/schema/suffixes/MTsat.yaml b/src/schema/suffixes/MTsat.yaml
deleted file mode 100644
index f708c2bd16..0000000000
--- a/src/schema/suffixes/MTsat.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Magnetization transfer saturation image
-description: |
-  In arbitrary units (arbitrary).
-  MTsat maps are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-unit: arbitrary
diff --git a/src/schema/suffixes/MWFmap.yaml b/src/schema/suffixes/MWFmap.yaml
deleted file mode 100644
index f6d95736ee..0000000000
--- a/src/schema/suffixes/MWFmap.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: Myelin water fraction image
-description: |
-  In arbitrary units (arbitrary).
-  MWF maps are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-  MWF intensity values are RECOMMENDED to be represented in percentage in the
-  range of 0-100%.
-unit: arbitrary
-minValue: 0
-maxValue: 100
diff --git a/src/schema/suffixes/PD.yaml b/src/schema/suffixes/PD.yaml
deleted file mode 100644
index 2a7b928606..0000000000
--- a/src/schema/suffixes/PD.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Proton density image
-description: |
-  Ambiguous, may refer to a parametric image or to a conventional image.
-  **Change:** Replaced by `PDw` or `PDmap`.
-unit: arbitrary
diff --git a/src/schema/suffixes/PDT2.yaml b/src/schema/suffixes/PDT2.yaml
deleted file mode 100644
index 2a31c9cfcb..0000000000
--- a/src/schema/suffixes/PDT2.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: PD and T2 weighted image
-description: |
-  In arbitrary units (arbitrary).
-  PDw and T2w images acquired using a dual echo FSE sequence through view
-  sharing process
-  ([Johnson et al. 1994](https://pubmed.ncbi.nlm.nih.gov/8010268/)).
-unit: arbitrary
diff --git a/src/schema/suffixes/PDT2map.yaml b/src/schema/suffixes/PDT2map.yaml
deleted file mode 100644
index 10d5d08829..0000000000
--- a/src/schema/suffixes/PDT2map.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Combined PD/T2 image
-description: |
-  In arbitrary units (arbitrary).
-  Combined PD/T2 maps are REQUIRED to use this suffix regardless of the method
-  used to generate them.
-unit: arbitrary
diff --git a/src/schema/suffixes/PDmap.yaml b/src/schema/suffixes/PDmap.yaml
deleted file mode 100644
index 51b4d02102..0000000000
--- a/src/schema/suffixes/PDmap.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Proton density image
-description: |
-  In arbitrary units (arbitrary).
-  PD maps are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-unit: arbitrary
diff --git a/src/schema/suffixes/PDw.yaml b/src/schema/suffixes/PDw.yaml
deleted file mode 100644
index 94a259f393..0000000000
--- a/src/schema/suffixes/PDw.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: Proton density (PD) weighted image
-description: |
-  In arbitrary units (arbitrary).
-  The contrast of these images is mainly determined by spatial variations in
-  the spin density (1H) of the imaged specimen.
-  In spin-echo sequences this contrast is achieved at short repetition and long
-  echo times.
-  In a gradient-echo acquisition, PD weighting dominates the contrast at long
-  repetition and short echo times, and at small flip angles.
-unit: arbitrary
diff --git a/src/schema/suffixes/R1map.yaml b/src/schema/suffixes/R1map.yaml
deleted file mode 100644
index 5d6721d2c4..0000000000
--- a/src/schema/suffixes/R1map.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Longitudinal relaxation rate image
-description: |
-  In seconds<sup>-1</sup> (1/s).
-  R1 maps (R1 = 1/T1) are REQUIRED to use this suffix regardless of the method
-  used to generate them.
-unit: 1/s
diff --git a/src/schema/suffixes/R2map.yaml b/src/schema/suffixes/R2map.yaml
deleted file mode 100644
index fb43e69981..0000000000
--- a/src/schema/suffixes/R2map.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: True transverse relaxation rate image
-description: |
-  In seconds<sup>-1</sup> (1/s).
-  R2 maps (R2 = 1/T2) are REQUIRED to use this suffix regardless of the method
-  used to generate them.
-unit: 1/s
diff --git a/src/schema/suffixes/R2starmap.yaml b/src/schema/suffixes/R2starmap.yaml
deleted file mode 100644
index 5306f9fe1e..0000000000
--- a/src/schema/suffixes/R2starmap.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Observed transverse relaxation rate image
-description: |
-  In seconds<sup>-1</sup> (1/s).
-  R2-star maps (R2star = 1/T2star) are REQUIRED to use this suffix regardless
-  of the method used to generate them.
-unit: 1/s
diff --git a/src/schema/suffixes/RB1COR.yaml b/src/schema/suffixes/RB1COR.yaml
deleted file mode 100644
index 404432908e..0000000000
--- a/src/schema/suffixes/RB1COR.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: RB1COR
-description: |
-  Low resolution images acquired by the body coil
-  (in the gantry of the scanner) and the head coil using identical acquisition
-  parameters to generate a combined sensitivity map as described in
-  [Papp et al. (2016)](https://doi.org/10.1002/mrm.26058).
diff --git a/src/schema/suffixes/RB1map.yaml b/src/schema/suffixes/RB1map.yaml
deleted file mode 100644
index 0202e74ad3..0000000000
--- a/src/schema/suffixes/RB1map.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: RF receive sensitivity map
-description: |
-  In arbitrary units (arbitrary).
-  Radio frequency (RF) receive (B1-) sensitivity maps are REQUIRED to use this
-  suffix regardless of the method used to generate them.
-  RB1map intensity values are RECOMMENDED to be represented as percent
-  multiplicative factors such that Amplitude<sub>effective</sub> =
-  B1-<sub>intensity</sub>\*Amplitude<sub>ideal</sub>.
-unit: arbitrary
diff --git a/src/schema/suffixes/S0map.yaml b/src/schema/suffixes/S0map.yaml
deleted file mode 100644
index e8f8f8a273..0000000000
--- a/src/schema/suffixes/S0map.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
----
-name: Observed signal amplitude (S0) image
-description: |
-  In arbitrary units (arbitrary).
-  For a multi-echo (typically fMRI) sequence, S0 maps index the baseline signal
-  before exponential (T2-star) signal decay.
-  In other words: the exponential of the intercept for a linear decay model
-  across log-transformed echos. For more information, please see, for example,
-  [the tedana documentation](https://tedana.readthedocs.io/en/latest/\
-  approach.html#monoexponential-decay-model-fit).
-  S0 maps are RECOMMENDED to use this suffix if derived from an ME-FMRI dataset.
diff --git a/src/schema/suffixes/T1map.yaml b/src/schema/suffixes/T1map.yaml
deleted file mode 100644
index 8aea121aee..0000000000
--- a/src/schema/suffixes/T1map.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: Longitudinal relaxation time image
-description: |
-  In seconds (s).
-  T1 maps are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-  See [this interactive book on T1 mapping](https://qmrlab.org/t1_book/intro)
-  for further reading on T1-mapping.
-unit: s
diff --git a/src/schema/suffixes/T1rho.yaml b/src/schema/suffixes/T1rho.yaml
deleted file mode 100644
index 3d39ee40d1..0000000000
--- a/src/schema/suffixes/T1rho.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: T1 in rotating frame (T1 rho) image
-description: |
-  In seconds (s).
-  T1-rho maps are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-unit: s
diff --git a/src/schema/suffixes/T1w.yaml b/src/schema/suffixes/T1w.yaml
deleted file mode 100644
index 68c81a8d32..0000000000
--- a/src/schema/suffixes/T1w.yaml
+++ /dev/null
@@ -1,14 +0,0 @@
----
-name: T1-weighted image
-description: |
-  In arbitrary units (arbitrary).
-  The contrast of these images is mainly determined by spatial variations in
-  the longitudinal relaxation time of the imaged specimen.
-  In spin-echo sequences this contrast is achieved at relatively short
-  repetition and echo times.
-  To achieve this weighting in gradient-echo images, again, short repetition
-  and echo times are selected; however, at relatively large flip angles.
-  Another common approach to increase T1 weighting in gradient-echo images is
-  to add an inversion preparation block to the beginning of the imaging
-  sequence (for example, `TurboFLASH` or `MP-RAGE`).
-unit: arbitrary
diff --git a/src/schema/suffixes/T2map.yaml b/src/schema/suffixes/T2map.yaml
deleted file mode 100644
index e6f99e1599..0000000000
--- a/src/schema/suffixes/T2map.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: True transverse relaxation time image
-description: |
-  In seconds (s).
-  T2 maps are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-unit: s
diff --git a/src/schema/suffixes/T2star.yaml b/src/schema/suffixes/T2star.yaml
deleted file mode 100644
index 1af9d615c1..0000000000
--- a/src/schema/suffixes/T2star.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: T2\* image
-description: |
-  Ambiguous, may refer to a parametric image or to a conventional image.
-  **Change:** Replaced by `T2starw` or `T2starmap`.
-anyOf:
-  - unit: arbitrary
-  - unit: s
diff --git a/src/schema/suffixes/T2starmap.yaml b/src/schema/suffixes/T2starmap.yaml
deleted file mode 100644
index 479762abd9..0000000000
--- a/src/schema/suffixes/T2starmap.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Observed transverse relaxation time image
-description: |
-  In seconds (s).
-  T2-star maps are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-unit: s
diff --git a/src/schema/suffixes/T2starw.yaml b/src/schema/suffixes/T2starw.yaml
deleted file mode 100644
index 6e3ede6b71..0000000000
--- a/src/schema/suffixes/T2starw.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
----
-name: T2star weighted image
-description: |
-  In arbitrary units (arbitrary).
-  The contrast of these images is mainly determined by spatial variations in
-  the (observed) transverse relaxation time of the imaged specimen.
-  In spin-echo sequences, this effect is negated as the excitation is followed
-  by an inversion pulse.
-  The contrast of gradient-echo images natively depends on T2-star effects.
-  However, for T2-star variation to dominate the image contrast,
-  gradient-echo acquisitions are carried out at long repetition and echo times,
-  and at small flip angles.
-unit: arbitrary
diff --git a/src/schema/suffixes/T2w.yaml b/src/schema/suffixes/T2w.yaml
deleted file mode 100644
index c2390df393..0000000000
--- a/src/schema/suffixes/T2w.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: T2-weighted image
-description: |
-  In arbitrary units (arbitrary).
-  The contrast of these images is mainly determined by spatial variations in
-  the (true) transverse relaxation time of the imaged specimen.
-  In spin-echo sequences this contrast is achieved at relatively long
-  repetition and echo times.
-  Generally, gradient echo sequences are not the most suitable option for
-  achieving T2 weighting, as their contrast natively depends on T2-star rather
-  than on T2.
-unit: arbitrary
diff --git a/src/schema/suffixes/TB1AFI.yaml b/src/schema/suffixes/TB1AFI.yaml
deleted file mode 100644
index a18a3e2091..0000000000
--- a/src/schema/suffixes/TB1AFI.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: TB1AFI
-description: |
-  This method ([Yarnykh 2007](https://doi.org/10.1002/mrm.21120))
-  calculates a B1<sup>+</sup> map from two images acquired at interleaved (two)
-  TRs with identical RF pulses using a steady-state sequence.
diff --git a/src/schema/suffixes/TB1DAM.yaml b/src/schema/suffixes/TB1DAM.yaml
deleted file mode 100644
index abb23b39f3..0000000000
--- a/src/schema/suffixes/TB1DAM.yaml
+++ /dev/null
@@ -1,9 +0,0 @@
----
-name: TB1DAM
-description: |
-  The double-angle B1<sup>+</sup> method
-  ([Insko and Bolinger 1993](https://doi.org/10.1006/jmra.1993.1133)) is based
-  on the calculation of the actual angles from signal ratios,
-  collected by two acquisitions at different nominal excitation flip angles.
-  Common sequence types for this application include spin echo and echo planar
-  imaging.
diff --git a/src/schema/suffixes/TB1EPI.yaml b/src/schema/suffixes/TB1EPI.yaml
deleted file mode 100644
index d67422c8ea..0000000000
--- a/src/schema/suffixes/TB1EPI.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: TB1EPI
-description: |
-  This B1<sup>+</sup> mapping method
-  ([Jiru and Klose 2006](https://doi.org/10.1002/mrm.21083)) is based on two
-  EPI readouts to acquire spin echo (SE) and stimulated echo (STE) images at
-  multiple flip angles in one sequence, used in the calculation of deviations
-  from the nominal flip angle.
diff --git a/src/schema/suffixes/TB1RFM.yaml b/src/schema/suffixes/TB1RFM.yaml
deleted file mode 100644
index 12e73de764..0000000000
--- a/src/schema/suffixes/TB1RFM.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: TB1RFM
-description: |
-  The result of a Siemens `rf_map` product sequence.
-  This sequence produces two images.
-  The first image appears like an anatomical image and the second output is a
-  scaled flip angle map.
diff --git a/src/schema/suffixes/TB1SRGE.yaml b/src/schema/suffixes/TB1SRGE.yaml
deleted file mode 100644
index 5e67f92980..0000000000
--- a/src/schema/suffixes/TB1SRGE.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: TB1SRGE
-description: |
-  Saturation-prepared with 2 rapid gradient echoes (SA2RAGE) uses a ratio of
-  two saturation recovery images with different time delays,
-  and a simulated look-up table to estimate B1+
-  ([Eggenschwiler et al. 2011](https://doi.org/10.1002/mrm.23145)).
-  This sequence can also be used in conjunction with MP2RAGE T1 mapping to
-  iteratively improve B1+ and T1 map estimation
-  ([Marques & Gruetter 2013](https://doi.org/10.1371/journal.pone.0069294)).
diff --git a/src/schema/suffixes/TB1TFL.yaml b/src/schema/suffixes/TB1TFL.yaml
deleted file mode 100644
index 5c60475469..0000000000
--- a/src/schema/suffixes/TB1TFL.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: TB1TFL
-description: |
-  The result of a Siemens `tfl_b1_map` product sequence.
-  This sequence produces two images.
-  The first image appears like an anatomical image and the second output is a
-  scaled flip angle map.
diff --git a/src/schema/suffixes/TB1map.yaml b/src/schema/suffixes/TB1map.yaml
deleted file mode 100644
index 5c26e19f12..0000000000
--- a/src/schema/suffixes/TB1map.yaml
+++ /dev/null
@@ -1,10 +0,0 @@
----
-name: RF transmit field image
-description: |
-  In arbitrary units (arbitrary).
-  Radio frequency (RF) transmit (B1+) field maps are REQUIRED to use this
-  suffix regardless of the method used to generate them.
-  TB1map intensity values are RECOMMENDED to be represented as percent
-  multiplicative factors such that FlipAngle<sub>effective</sub> =
-  B1+<sub>intensity</sub>\*FlipAngle<sub>nominal</sub> .
-unit: arbitrary
diff --git a/src/schema/suffixes/UNIT1.yaml b/src/schema/suffixes/UNIT1.yaml
deleted file mode 100644
index db9a62be72..0000000000
--- a/src/schema/suffixes/UNIT1.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: Homogeneous (flat) T1-weighted MP2RAGE image
-description: |
-  In arbitrary units (arbitrary).
-  UNIT1 images are REQUIRED to use this suffix regardless of the method used to
-  generate them.
-  Note that although this image is T1-weighted, regions without MR signal will
-  contain white salt-and-pepper noise that most segmentation algorithms will
-  fail on.
-  Therefore, it is important to dissociate it from from `T1w`.
-  Please see [`MP2RAGE` specific notes](/99-appendices/11-qmri.html#unit1-images)
-  in the qMRI appendix for further information.
diff --git a/src/schema/suffixes/VFA.yaml b/src/schema/suffixes/VFA.yaml
deleted file mode 100644
index fbdedad562..0000000000
--- a/src/schema/suffixes/VFA.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: Variable flip angle
-description: |
-  The VFA method involves at least two spoiled gradient echo (SPGR) of
-  steady-state free precession (SSFP) images acquired at different flip angles.
-  Depending on the provided metadata fields and the sequence type,
-  data may be eligible for DESPOT1, DESPOT2 and their variants
-  ([Deoni et al. 2005](https://doi.org/10.1002/mrm.20314)).
diff --git a/src/schema/suffixes/_template.yaml b/src/schema/suffixes/_template.yaml
deleted file mode 100644
index d5f7e6e4e8..0000000000
--- a/src/schema/suffixes/_template.yaml
+++ /dev/null
@@ -1,3 +0,0 @@
----
-name:
-description:
diff --git a/src/schema/suffixes/angio.yaml b/src/schema/suffixes/angio.yaml
deleted file mode 100644
index f9dae61183..0000000000
--- a/src/schema/suffixes/angio.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Angiogram
-description: |
-  Magnetic resonance angiography sequences focus on enhancing the contrast of
-  blood vessels (generally arteries, but sometimes veins) against other tissue
-  types.
diff --git a/src/schema/suffixes/asl.yaml b/src/schema/suffixes/asl.yaml
deleted file mode 100644
index deade6a50b..0000000000
--- a/src/schema/suffixes/asl.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Arterial Spin Labeling
-description: |
-  The complete ASL time series stored as a 4D NIfTI file in the original
-  acquisition order, with possible volume types including: control, label,
-  m0scan, deltam, cbf.
diff --git a/src/schema/suffixes/aslcontext.yaml b/src/schema/suffixes/aslcontext.yaml
deleted file mode 100644
index 75e6851bf4..0000000000
--- a/src/schema/suffixes/aslcontext.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Arterial Spin Labeling Context
-description: |
-  A TSV file defining the image types for volumes in an associated ASL file.
diff --git a/src/schema/suffixes/asllabeling.yaml b/src/schema/suffixes/asllabeling.yaml
deleted file mode 100644
index 7a4043622c..0000000000
--- a/src/schema/suffixes/asllabeling.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: ASL Labeling Screenshot
-description: |
-  An anonymized screenshot of the planning of the labeling slab/plane with
-  respect to the imaging slab or slices `*_asllabeling.jpg`.
-  Based on DICOM macro C.8.13.5.14.
diff --git a/src/schema/suffixes/beh.yaml b/src/schema/suffixes/beh.yaml
deleted file mode 100644
index a6c99ba991..0000000000
--- a/src/schema/suffixes/beh.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Behavioral recording
-description: |
-  Behavioral recordings from tasks.
-  These files are similar to events files, but do not include the `"onset"` and
-  `"duration"` columns that are mandatory for events files.
diff --git a/src/schema/suffixes/blood.yaml b/src/schema/suffixes/blood.yaml
deleted file mode 100644
index b162a421b6..0000000000
--- a/src/schema/suffixes/blood.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Blood recording data
-description: |
-  Blood measurements of radioactivity stored in
-  [tabular files](/02-common-principles.html#tabular-files)
-  and located in the `pet/` directory along with the corresponding PET data.
diff --git a/src/schema/suffixes/bold.yaml b/src/schema/suffixes/bold.yaml
deleted file mode 100644
index fbc624fed9..0000000000
--- a/src/schema/suffixes/bold.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Blood-Oxygen-Level Dependent image
-description: |
-  Blood-Oxygen-Level Dependent contrast (specialized T2\* weighting)
diff --git a/src/schema/suffixes/cbv.yaml b/src/schema/suffixes/cbv.yaml
deleted file mode 100644
index 344e42ce65..0000000000
--- a/src/schema/suffixes/cbv.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Cerebral blood volume image
-description: |
-  Cerebral Blood Volume contrast (specialized T2\* weighting or difference between T1 weighted images)
diff --git a/src/schema/suffixes/channels.yaml b/src/schema/suffixes/channels.yaml
deleted file mode 100644
index cc4d529767..0000000000
--- a/src/schema/suffixes/channels.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Channels File
-description: |
-  Channel information.
diff --git a/src/schema/suffixes/coordsystem.yaml b/src/schema/suffixes/coordsystem.yaml
deleted file mode 100644
index d3228210d1..0000000000
--- a/src/schema/suffixes/coordsystem.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Coordinate System File
-description: |
-  A JSON document specifying the coordinate system(s) used for the MEG, EEG,
-  head localization coils, and anatomical landmarks.
diff --git a/src/schema/suffixes/defacemask.yaml b/src/schema/suffixes/defacemask.yaml
deleted file mode 100644
index 32fa386ac2..0000000000
--- a/src/schema/suffixes/defacemask.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Defacing Mask
-description: |
-  A binary mask that was used to remove facial features from an anatomical MRI
-  image.
diff --git a/src/schema/suffixes/dwi.yaml b/src/schema/suffixes/dwi.yaml
deleted file mode 100644
index a3c63a101a..0000000000
--- a/src/schema/suffixes/dwi.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Diffusion-weighted image
-description: |
-  Diffusion-weighted imaging contrast (specialized T2\* weighting).
diff --git a/src/schema/suffixes/eeg.yaml b/src/schema/suffixes/eeg.yaml
deleted file mode 100644
index 6aa40fdf39..0000000000
--- a/src/schema/suffixes/eeg.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Electroencephalography
-description: |
-  Electroencephalography recording data.
diff --git a/src/schema/suffixes/electrodes.yaml b/src/schema/suffixes/electrodes.yaml
deleted file mode 100644
index 056e5fb046..0000000000
--- a/src/schema/suffixes/electrodes.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Electrodes
-description: |
-  File that gives the location of (i)EEG electrodes.
diff --git a/src/schema/suffixes/epi.yaml b/src/schema/suffixes/epi.yaml
deleted file mode 100644
index 2c8600f63f..0000000000
--- a/src/schema/suffixes/epi.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: EPI
-description: |
-  The phase-encoding polarity (PEpolar) technique combines two or more Spin Echo
-  EPI scans with different phase encoding directions to estimate the underlying
-  inhomogeneity/deformation map.
diff --git a/src/schema/suffixes/events.yaml b/src/schema/suffixes/events.yaml
deleted file mode 100644
index 0e53d7d34e..0000000000
--- a/src/schema/suffixes/events.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Events
-description: |
-  Event timing information from a behavioral task.
diff --git a/src/schema/suffixes/fieldmap.yaml b/src/schema/suffixes/fieldmap.yaml
deleted file mode 100644
index bbce32c57f..0000000000
--- a/src/schema/suffixes/fieldmap.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Fieldmap
-description: |
-  Some MR schemes such as spiral-echo imaging (SEI) sequences are able to
-  directly provide maps of the *B<sub>0</sub>* field inhomogeneity.
diff --git a/src/schema/suffixes/headshape.yaml b/src/schema/suffixes/headshape.yaml
deleted file mode 100644
index f4a53833a9..0000000000
--- a/src/schema/suffixes/headshape.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Headshape File
-description: |
-  The 3-D locations of points that describe the head shape and/or electrode
-  locations can be digitized and stored in separate files.
diff --git a/src/schema/suffixes/ieeg.yaml b/src/schema/suffixes/ieeg.yaml
deleted file mode 100644
index dd670af006..0000000000
--- a/src/schema/suffixes/ieeg.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Intracranial Electroencephalography
-description: |
-  Intracranial electroencephalography recording data.
diff --git a/src/schema/suffixes/inplaneT1.yaml b/src/schema/suffixes/inplaneT1.yaml
deleted file mode 100644
index aca7bf2f4f..0000000000
--- a/src/schema/suffixes/inplaneT1.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Inplane T1
-description: |
-  In arbitrary units (arbitrary).
-  T1 weighted structural image matched to a functional (task) image.
-unit: arbitrary
diff --git a/src/schema/suffixes/inplaneT2.yaml b/src/schema/suffixes/inplaneT2.yaml
deleted file mode 100644
index 8fe58a0bdf..0000000000
--- a/src/schema/suffixes/inplaneT2.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Inplane T2
-description: |
-  In arbitrary units (arbitrary).
-  T2 weighted structural image matched to a functional (task) image.
-unit: arbitrary
diff --git a/src/schema/suffixes/m0scan.yaml b/src/schema/suffixes/m0scan.yaml
deleted file mode 100644
index 78b04cc145..0000000000
--- a/src/schema/suffixes/m0scan.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: M0 image
-description: |
-  The M0 image is a calibration image, used to estimate the equilibrium
-  magnetization of blood.
diff --git a/src/schema/suffixes/magnitude.yaml b/src/schema/suffixes/magnitude.yaml
deleted file mode 100644
index 22d5aa6560..0000000000
--- a/src/schema/suffixes/magnitude.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-name: Magnitude
-description: |
-  Field-mapping MR schemes such as gradient-recalled echo (GRE) generate a
-  Magnitude image to be used for anatomical reference.
-  Requires the existence of Phase, Phase-difference or Fieldmap maps.
diff --git a/src/schema/suffixes/magnitude1.yaml b/src/schema/suffixes/magnitude1.yaml
deleted file mode 100644
index e9787e617f..0000000000
--- a/src/schema/suffixes/magnitude1.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Magnitude
-description: |
-  Magnitude map generated by GRE or similar schemes, associated with the first
-  echo in the sequence.
diff --git a/src/schema/suffixes/magnitude2.yaml b/src/schema/suffixes/magnitude2.yaml
deleted file mode 100644
index c4f056ed07..0000000000
--- a/src/schema/suffixes/magnitude2.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Magnitude
-description: |
-  Magnitude map generated by GRE or similar schemes, associated with the second
-  echo in the sequence.
diff --git a/src/schema/suffixes/markers.yaml b/src/schema/suffixes/markers.yaml
deleted file mode 100644
index 8ab8dd9fb6..0000000000
--- a/src/schema/suffixes/markers.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
----
-name: MEG Sensor Coil Positions
-description: |
-  Another manufacturer-specific detail pertains to the KIT/Yokogawa/Ricoh
-  system, which saves the MEG sensor coil positions in a separate file with two
-  possible filename extensions  (`.sqd`, `.mrk`).
-  For these files, the `markers` suffix MUST be used.
-  For example: `sub-01_task-nback_markers.sqd`
diff --git a/src/schema/suffixes/meg.yaml b/src/schema/suffixes/meg.yaml
deleted file mode 100644
index 713d402075..0000000000
--- a/src/schema/suffixes/meg.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Magnetoencephalography
-description: |
-  Unprocessed MEG data stored in the native file format of the MEG instrument
-  with which the data was collected.
diff --git a/src/schema/suffixes/pet.yaml b/src/schema/suffixes/pet.yaml
deleted file mode 100644
index ce4135481a..0000000000
--- a/src/schema/suffixes/pet.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Positron Emission Tomography
-description: |
-  PET imaging data SHOULD be stored in 4D
-  (or 3D, if only one volume was acquired) NIfTI files with the `_pet` suffix.
-  Volumes MUST be stored in chronological order
-  (the order they were acquired in).
diff --git a/src/schema/suffixes/phase.yaml b/src/schema/suffixes/phase.yaml
deleted file mode 100644
index 2c3e17cac8..0000000000
--- a/src/schema/suffixes/phase.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
----
-name: Phase image
-description: |
-  [DEPRECATED](/02-common-principles.html#definitions).
-  Phase information associated with magnitude information stored in BOLD
-  contrast.
-  This suffix should be replaced by the
-  [`part-phase`](/99-appendices/09-entities.html#part)
-  in conjunction with the `bold` suffix.
-anyOf:
-  - unit: arbitrary
-  - unit: rad
diff --git a/src/schema/suffixes/phase1.yaml b/src/schema/suffixes/phase1.yaml
deleted file mode 100644
index d0dadf485c..0000000000
--- a/src/schema/suffixes/phase1.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Phase
-description: |
-  Phase map generated by GRE or similar schemes, associated with the first
-  echo in the sequence.
diff --git a/src/schema/suffixes/phase2.yaml b/src/schema/suffixes/phase2.yaml
deleted file mode 100644
index 757afefca6..0000000000
--- a/src/schema/suffixes/phase2.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Phase
-description: |
-  Phase map generated by GRE or similar schemes, associated with the second
-  echo in the sequence.
diff --git a/src/schema/suffixes/phasediff.yaml b/src/schema/suffixes/phasediff.yaml
deleted file mode 100644
index bf67fa2dfe..0000000000
--- a/src/schema/suffixes/phasediff.yaml
+++ /dev/null
@@ -1,7 +0,0 @@
----
-name: Phase-difference
-description: |
-  Some scanners subtract the `phase1` from the `phase2` map and generate a
-  unique `phasediff` file.
-  For instance, this is a common output for the built-in fieldmap sequence of
-  Siemens scanners.
diff --git a/src/schema/suffixes/photo.yaml b/src/schema/suffixes/photo.yaml
deleted file mode 100644
index fb715f0ece..0000000000
--- a/src/schema/suffixes/photo.yaml
+++ /dev/null
@@ -1,5 +0,0 @@
----
-name: Photo File
-description: |
-  Photos of the anatomical landmarks and/or head localization coils
-  (`*_photo.jpg`).
diff --git a/src/schema/suffixes/physio.yaml b/src/schema/suffixes/physio.yaml
deleted file mode 100644
index 971d80d377..0000000000
--- a/src/schema/suffixes/physio.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Physiological recording
-description: |
-  Physiological recordings such as cardiac and respiratory signals.
diff --git a/src/schema/suffixes/sbref.yaml b/src/schema/suffixes/sbref.yaml
deleted file mode 100644
index 3f209f4f23..0000000000
--- a/src/schema/suffixes/sbref.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Single-band reference image
-description: |
-  Single-band reference for one or more multi-band `dwi` images.
diff --git a/src/schema/suffixes/stim.yaml b/src/schema/suffixes/stim.yaml
deleted file mode 100644
index ec1eba6b7f..0000000000
--- a/src/schema/suffixes/stim.yaml
+++ /dev/null
@@ -1,4 +0,0 @@
----
-name: Continuous recording
-description: |
-  Continuous measures, such as parameters of a film or audio stimulus.
diff --git a/tools/schemacode/schema.py b/tools/schemacode/schema.py
index 472efc0df3..8a9c137ccf 100644
--- a/tools/schemacode/schema.py
+++ b/tools/schemacode/schema.py
@@ -2,10 +2,10 @@
 """
 import logging
 import os
+import os.path as op
 from copy import deepcopy
+from glob import glob
 from pathlib import Path
-from warnings import warn
-from pprint import pprint
 
 import pandas as pd
 import yaml
@@ -30,24 +30,24 @@ def _get_entry_name(path):
         return path.name
 
 
-def dereference_yaml(struct, path):
+def dereference_yaml(schema, struct):
     """Recursively search a dictionary-like object for $ref keys.
 
-    Each $ref key is replaced with the contents of the referenced file.
+    Each $ref key is replaced with the contents of the referenced field in the overall
+    dictionary-like object.
     """
     if isinstance(struct, dict):
         if "$ref" in struct:
-            with open(os.path.join(path, struct["$ref"]), "r") as fo:
-                template = yaml.load(fo, Loader=yaml.SafeLoader)
-
+            ref_field = struct["$ref"]
+            template = schema[ref_field]
             struct.pop("$ref")
             # Result is template object with local overrides
             struct = {**template, **struct}
 
-        struct = {key: dereference_yaml(val, path) for key, val in struct.items()}
+        struct = {key: dereference_yaml(schema, val) for key, val in struct.items()}
 
     elif isinstance(struct, list):
-        struct = [dereference_yaml(item, path) for item in struct]
+        struct = [dereference_yaml(schema, item) for item in struct]
 
     return struct
 
@@ -72,23 +72,46 @@ def load_schema(schema_path):
         Schema in dictionary form.
     """
     schema_path = Path(schema_path)
-    if schema_path.is_file() and (schema_path.suffix == ".yaml"):
-        base_path = os.path.dirname(schema_path.absolute())
-        with open(schema_path) as f:
-            dict_ = dereference_yaml(
-                yaml.load(f, Loader=yaml.SafeLoader),
-                base_path
-            )
-            return dict_
-    elif schema_path.is_dir():
-        # iterate through files and subdirectories
-        res = {
-            _get_entry_name(path): load_schema(path)
-            for path in sorted(schema_path.iterdir())
-        }
-        return {k: v for k, v in res.items() if v is not None}
-    else:
-        warn(f"{schema_path} is somehow nothing we can load")
+    objects_dir = schema_path / "objects/"
+    rules_dir = schema_path / "rules/"
+
+    schema = {}
+    schema["objects"] = {}
+    schema["rules"] = {}
+
+    # Load object definitions. All are present in single files.
+    object_group_files = sorted(glob(str(objects_dir / "*.yaml")))
+    for object_group_file in object_group_files:
+        group_name = op.splitext(op.basename(object_group_file))[0]
+        with open(object_group_file, "r") as fo:
+            dict_ = yaml.load(fo, Loader=yaml.SafeLoader)
+            dict_ = dereference_yaml(dict_, dict_)
+            schema["objects"][group_name] = dict_
+
+    # Grab single-file rule groups
+    rule_group_files = sorted(glob(str(rules_dir / "*.yaml")))
+    rule_group_folders = sorted(glob(str(rules_dir / "*")))
+    rule_group_folders = [f for f in rule_group_folders if op.isdir(f)]
+    for rule_group_file in rule_group_files:
+        group_name = op.splitext(op.basename(rule_group_file))[0]
+        with open(rule_group_file, "r") as fo:
+            dict_ = yaml.load(fo, Loader=yaml.SafeLoader)
+            dict_ = dereference_yaml(dict_, dict_)
+            schema["rules"][group_name] = dict_
+
+    # Load folders of rule subgroups.
+    for rule_group_folder in rule_group_folders:
+        group_name = op.basename(rule_group_folder)
+        rule_subgroup_files = sorted(glob(op.join(rule_group_folder, "*.yaml")))
+        schema["rules"][group_name] = {}
+        for rule_subgroup_file in rule_subgroup_files:
+            subgroup_name = op.splitext(op.basename(rule_subgroup_file))[0]
+            with open(rule_subgroup_file, "r") as fo:
+                dict_ = yaml.load(fo, Loader=yaml.SafeLoader)
+                dict_ = dereference_yaml(dict_, dict_)
+                schema["rules"][group_name][subgroup_name] = dict_
+
+    return schema
 
 
 def filter_schema(schema, **kwargs):
@@ -160,10 +183,12 @@ def make_entity_definitions(schema):
         A string containing descriptions and some formatting
         information about the entities in the schema.
     """
-    entities = schema["entities"]
+    entity_order = schema["rules"]["entities"]
+    entity_definitions = schema["objects"]["entities"]
 
     text = ""
-    for entity, entity_info in entities.items():
+    for entity in entity_order:
+        entity_info = entity_definitions[entity]
         entity_shorthand = entity_info["entity"]
         text += "\n"
         text += "## {}".format(entity_shorthand)
@@ -204,27 +229,28 @@ def make_filename_template(schema, **kwargs):
         in the schema, after filtering.
     """
     schema = filter_schema(schema, **kwargs)
-    entities = list(schema["entities"].keys())
+
+    entity_order = schema["rules"]["entities"]
 
     paragraph = ""
     # Parent folders
     paragraph += "{}-<{}>/\n\t[{}-<{}>/]\n".format(
-        schema["entities"]["subject"]["entity"],
-        schema["entities"]["subject"]["format"],
-        schema["entities"]["session"]["entity"],
-        schema["entities"]["session"]["format"],
+        schema["objects"]["entities"]["subject"]["entity"],
+        schema["objects"]["entities"]["subject"]["format"],
+        schema["objects"]["entities"]["session"]["entity"],
+        schema["objects"]["entities"]["session"]["format"],
     )
 
-    for datatype in schema["datatypes"].keys():
+    for datatype in schema["rules"]["datatypes"].keys():
         paragraph += "\t\t{}/\n".format(datatype)
 
         # Unique filename patterns
-        for group in schema["datatypes"][datatype]:
+        for group in schema["rules"]["datatypes"][datatype]:
             string = "\t\t\t"
-            for ent in entities:
+            for ent in entity_order:
                 ent_format = "{}-<{}>".format(
-                    schema["entities"][ent]["entity"],
-                    schema["entities"][ent].get("format", "label")
+                    schema["objects"]["entities"][ent]["entity"],
+                    schema["objects"]["entities"][ent].get("format", "label")
                 )
                 if ent in group["entities"]:
                     if group["entities"][ent] == "required":
@@ -310,8 +336,8 @@ def make_entity_table(schema, tablefmt="github", **kwargs):
     table = [formats]
 
     # Compose header and formats first
-    for i, (entity, spec) in enumerate(schema["entities"].items()):
-        entity_shorthand = schema["entities"][entity]["entity"]
+    for i, (entity, spec) in enumerate(schema["objects"]["entities"].items()):
+        entity_shorthand = schema["objects"]["entities"][entity]["entity"]
         header.append(spec["name"])
         formats.append(
             f'[`{entity_shorthand}-<{spec.get("format", "label")}>`]'
@@ -320,7 +346,7 @@ def make_entity_table(schema, tablefmt="github", **kwargs):
         entity_to_col[entity] = i + 1
 
     # Go through data types
-    for dtype, dtype_specs in schema["datatypes"].items():
+    for dtype, dtype_specs in schema["rules"]["datatypes"].items():
         dtype_rows = {}
 
         # each dtype could have multiple specs
@@ -374,18 +400,20 @@ def make_entity_table(schema, tablefmt="github", **kwargs):
 
 def make_suffix_table(schema, suffixes, tablefmt="github"):
     """Produce suffix table (markdown) based on requested suffixes.
+
     Parameters
     ----------
     schema : dict
     suffixes : list of str
     tablefmt : str
+
     Returns
     -------
     table_str : str
         Tabulated table as a string.
     """
     # The filter function doesn't work here.
-    suffix_schema = schema["suffixes"]
+    suffix_schema = schema["objects"]["suffixes"]
 
     suffixes_found = [f for f in suffixes if f in suffix_schema.keys()]
     suffixes_not_found = [f for f in suffixes if f not in suffix_schema.keys()]
@@ -423,58 +451,6 @@ def make_suffix_table(schema, suffixes, tablefmt="github"):
     return table_str
 
 
-def _get_link(string):
-    refs = {
-        "array": "https://www.w3schools.com/js/js_json_arrays.asp",
-        "string": "https://www.w3schools.com/js/js_json_datatypes.asp",
-        "number": "https://www.w3schools.com/js/js_json_datatypes.asp",
-        "object": "https://www.json.org/json-en.html",
-        "integer": "https://www.w3schools.com/js/js_json_datatypes.asp",
-        "boolean": "https://www.w3schools.com/js/js_json_datatypes.asp",
-    }
-    # Allow plurals (e.g., strings -> links to string)
-    dtype = string[:-1] if string[-1] == "s" else string
-    url = refs.get(dtype)
-    if url:
-        return f"[{string}]({url})"
-    return string
-
-
-def _resolve_metadata_type(definition):
-    """Generate string of metadata type from dictionary."""
-    if "type" in definition.keys():
-        string = _get_link(definition["type"])
-
-        if definition.get("enum") == ["n/a"]:
-            # Special string case of n/a
-            string = '`"n/a"`'
-
-        elif "type" in definition.get("items", {}):
-            # Items within arrays
-            string += " of " + _get_link(definition["items"]["type"] + "s")
-
-        elif "type" in definition.get("additionalProperties", {}):
-            # Values within objects
-            string += " of " + _get_link(
-                definition["additionalProperties"]["type"] + "s"
-            )
-
-    elif "anyOf" in definition:
-        # Use dictionary to get unique substrings while preserving insertion order
-        substrings = {_resolve_metadata_type(subdict): None
-                      for subdict in definition["anyOf"]}
-
-        string = " or ".join(substrings)
-
-    else:
-        # A hack to deal with $ref in the current schema
-        print(f"Type could not be inferred for {definition['name']}")
-        pprint(definition)
-        string = "unknown"
-
-    return string
-
-
 def make_metadata_table(schema, field_info, tablefmt="github"):
     """Produce metadata table (markdown) based on requested fields.
 
@@ -501,7 +477,7 @@ def make_metadata_table(schema, field_info, tablefmt="github"):
     """
     fields = list(field_info.keys())
     # The filter function doesn't work here.
-    metadata_schema = schema["metadata"]
+    metadata_schema = schema["objects"]["metadata"]
 
     retained_fields = [f for f in fields if f in metadata_schema.keys()]
     dropped_fields = [f for f in fields if f not in metadata_schema.keys()]
@@ -527,7 +503,7 @@ def make_metadata_table(schema, field_info, tablefmt="github"):
             "[DEPRECATED](/02-common-principles.html#definitions)",
         )
 
-        type_string = _resolve_metadata_type(metadata_schema[field])
+        type_string = utils.resolve_metadata_type(metadata_schema[field])
 
         description = (
             metadata_schema[field]["description"] + " " + description_addendum
diff --git a/tools/schemacode/utils.py b/tools/schemacode/utils.py
index 36f449ee90..d6d95b6fc3 100644
--- a/tools/schemacode/utils.py
+++ b/tools/schemacode/utils.py
@@ -2,6 +2,7 @@
 """
 import logging
 import os.path as op
+from pprint import pprint
 
 import numpy as np
 
@@ -132,3 +133,55 @@ def flatten_multiindexed_columns(df):
     df.index.name = "Entity"
     df = df.drop(columns=["DataType"])
     return df
+
+
+def get_link(string):
+    refs = {
+        "array": "https://www.w3schools.com/js/js_json_arrays.asp",
+        "string": "https://www.w3schools.com/js/js_json_datatypes.asp",
+        "number": "https://www.w3schools.com/js/js_json_datatypes.asp",
+        "object": "https://www.json.org/json-en.html",
+        "integer": "https://www.w3schools.com/js/js_json_datatypes.asp",
+        "boolean": "https://www.w3schools.com/js/js_json_datatypes.asp",
+    }
+    # Allow plurals (e.g., strings -> links to string)
+    dtype = string[:-1] if string[-1] == "s" else string
+    url = refs.get(dtype)
+    if url:
+        return f"[{string}]({url})"
+    return string
+
+
+def resolve_metadata_type(definition):
+    """Generate string of metadata type from dictionary."""
+    if "type" in definition.keys():
+        string = get_link(definition["type"])
+
+        if definition.get("enum") == ["n/a"]:
+            # Special string case of n/a
+            string = '`"n/a"`'
+
+        elif "type" in definition.get("items", {}):
+            # Items within arrays
+            string += " of " + get_link(definition["items"]["type"] + "s")
+
+        elif "type" in definition.get("additionalProperties", {}):
+            # Values within objects
+            string += " of " + get_link(
+                definition["additionalProperties"]["type"] + "s"
+            )
+
+    elif "anyOf" in definition:
+        # Use dictionary to get unique substrings while preserving insertion order
+        substrings = {resolve_metadata_type(subdict): None
+                      for subdict in definition["anyOf"]}
+
+        string = " or ".join(substrings)
+
+    else:
+        # A hack to deal with $ref in the current schema
+        print(f"Type could not be inferred for {definition['name']}")
+        pprint(definition)
+        string = "unknown"
+
+    return string