diff --git a/extras/fileformats/extras/application/archive.py b/extras/fileformats/extras/application/archive.py
index 70a51e0..1d7bff1 100644
--- a/extras/fileformats/extras/application/archive.py
+++ b/extras/fileformats/extras/application/archive.py
@@ -10,7 +10,7 @@
 import pydra.engine.specs
 from fileformats.generic import FsObject
 from fileformats.core.utils import set_cwd
-from fileformats.core.type_aliases import PathType
+from fileformats.core.typing import PathType
 from fileformats.core import converter, FileSet
 from fileformats.application import Zip, Tar, TarGzip
 
@@ -238,4 +238,4 @@ def relative_path(path: PathType, base_dir: PathType) -> str:
             f"Cannot add {path} to archive as it is not a "
             f"subdirectory of {base_dir}"
         )
-    return relpath
+    return relpath  # type: ignore[no-any-return]
diff --git a/extras/fileformats/extras/application/serialization.py b/extras/fileformats/extras/application/serialization.py
index 0fdb189..65999d9 100644
--- a/extras/fileformats/extras/application/serialization.py
+++ b/extras/fileformats/extras/application/serialization.py
@@ -24,7 +24,7 @@ def convert_data_serialization(
     output_path = out_dir / (
         in_file.fspath.stem + (output_format.ext if output_format.ext else "")
     )
-    return output_format.save_new(output_path, dct)
+    return output_format.save_new(output_path, dct)  # type: ignore[no-any-return]
 
 
 @extra_implementation(DataSerialization.load)
diff --git a/extras/fileformats/extras/image/converters.py b/extras/fileformats/extras/image/converters.py
index db01286..89266b9 100644
--- a/extras/fileformats/extras/image/converters.py
+++ b/extras/fileformats/extras/image/converters.py
@@ -25,4 +25,4 @@ def convert_image(
     output_path = out_dir / (
         in_file.fspath.stem + (output_format.ext if output_format.ext else "")
     )
-    return output_format.save_new(output_path, data_array)
+    return output_format.save_new(output_path, data_array)  # type: ignore[no-any-return]
diff --git a/fileformats/application/serialization.py b/fileformats/application/serialization.py
index 1b23541..a454aea 100644
--- a/fileformats/application/serialization.py
+++ b/fileformats/application/serialization.py
@@ -1,6 +1,6 @@
 import json
 import typing as ty
-from typing_extensions import Self, TypeAlias
+from fileformats.core.typing import Self, TypeAlias
 from pathlib import Path
 from fileformats.core import extra, DataType, FileSet, extra_implementation
 from fileformats.core.mixin import WithClassifiers
diff --git a/fileformats/core/datatype.py b/fileformats/core/datatype.py
index 3c2846b..8e7d14f 100644
--- a/fileformats/core/datatype.py
+++ b/fileformats/core/datatype.py
@@ -1,7 +1,7 @@
 from __future__ import annotations
 from inspect import isclass
 import typing as ty
-from typing_extensions import Self
+from fileformats.core.typing import Self
 from abc import ABCMeta
 import importlib
 import itertools
@@ -27,7 +27,7 @@
 class DataType(Classifier, metaclass=ABCMeta):
     is_fileset = False
     is_field = False
-    nested_types: ty.Tuple[ty.Type["DataType"], ...] = ()
+    nested_types: ty.Tuple[ty.Type[Classifier], ...] = ()
     # Store converters registered by @converter decorator that convert to FileSet
     # NB: each class will have its own version of this dictionary
     converters: ty.Dict[
diff --git a/fileformats/core/extras.py b/fileformats/core/extras.py
index db666b2..3305123 100644
--- a/fileformats/core/extras.py
+++ b/fileformats/core/extras.py
@@ -5,7 +5,7 @@
 import functools
 import urllib.error
 import fileformats.core
-from typing_extensions import TypeAlias
+from fileformats.core.typing import TypeAlias
 from .datatype import DataType
 from .converter_helpers import ConverterWrapper, ConverterSpec, SubtypeVar
 from .exceptions import FormatConversionError, FileFormatsExtrasError
diff --git a/fileformats/core/fileset.py b/fileformats/core/fileset.py
index 919b770..5d87abb 100644
--- a/fileformats/core/fileset.py
+++ b/fileformats/core/fileset.py
@@ -14,7 +14,7 @@
 from pathlib import Path
 import hashlib
 import logging
-from typing_extensions import Self
+from fileformats.core.typing import Self
 from .utils import (
     classproperty,
     fspaths_converter,
@@ -22,7 +22,7 @@
     matching_source,
     import_extras_module,
 )
-from .type_aliases import FspathsInputType, CryptoMethod, PathType
+from .typing import FspathsInputType, CryptoMethod, PathType
 from .sampling import SampleFileGenerator
 from .identification import (
     to_mime_format_name,
diff --git a/fileformats/core/mixin.py b/fileformats/core/mixin.py
index b068184..97c2c5b 100644
--- a/fileformats/core/mixin.py
+++ b/fileformats/core/mixin.py
@@ -175,7 +175,7 @@ class MyFileFormatWithSeparateHeader(WithSeparateHeader, MyFileFormat):
     header_type: ty.Type["fileformats.core.FileSet"]
 
     @classproperty
-    def nested_types(cls) -> ty.Tuple[ty.Type["DataType"], ...]:
+    def nested_types(cls) -> ty.Tuple[ty.Type[Classifier], ...]:
         return (cls.header_type,)
 
     @property
@@ -235,7 +235,7 @@ def read_metadata(
         return metadata
 
     @classproperty
-    def nested_types(cls) -> ty.Tuple[ty.Type["DataType"], ...]:
+    def nested_types(cls) -> ty.Tuple[ty.Type[Classifier], ...]:
         return cls.side_car_types
 
 
@@ -316,7 +316,7 @@ def is_classified(cls) -> bool:
         return "unclassified" in cls.__dict__
 
     @classproperty
-    def nested_types(cls) -> ty.Tuple[ty.Type["DataType"], ...]:
+    def nested_types(cls) -> ty.Tuple[ty.Type[Classifier], ...]:
         return cls.classifiers
 
     @classmethod
diff --git a/fileformats/core/type_aliases.py b/fileformats/core/typing.py
similarity index 60%
rename from fileformats/core/type_aliases.py
rename to fileformats/core/typing.py
index 4825646..d7de7b6 100644
--- a/fileformats/core/type_aliases.py
+++ b/fileformats/core/typing.py
@@ -1,6 +1,11 @@
 import typing as ty
+import sys
 from pathlib import Path
-from typing_extensions import TypeAlias
+
+if sys.version_info[:2] < (3, 11):
+    from typing_extensions import TypeAlias, Self
+else:
+    from typing import TypeAlias, Self
 
 if ty.TYPE_CHECKING:
     import fileformats.core
@@ -15,3 +20,6 @@
 ]
 
 PathType: TypeAlias = ty.Union[str, Path]
+
+
+__all__ = ["CryptoMethod", "FspathsInputType", "PathType", "TypeAlias", "Self"]
diff --git a/fileformats/core/utils.py b/fileformats/core/utils.py
index 537d6a2..98c7101 100644
--- a/fileformats/core/utils.py
+++ b/fileformats/core/utils.py
@@ -10,7 +10,7 @@
 import logging
 import pkgutil
 from contextlib import contextmanager
-from .type_aliases import FspathsInputType
+from .typing import FspathsInputType
 import fileformats.core
 
 if ty.TYPE_CHECKING:
diff --git a/fileformats/generic/directory.py b/fileformats/generic/directory.py
index f107a65..b1a29fb 100644
--- a/fileformats/generic/directory.py
+++ b/fileformats/generic/directory.py
@@ -5,7 +5,7 @@
 from .fsobject import FsObject
 from fileformats.core.fileset import FileSet, FILE_CHUNK_LEN_DEFAULT
 from fileformats.core.mixin import WithClassifiers
-from fileformats.core.type_aliases import CryptoMethod
+from fileformats.core.typing import CryptoMethod
 
 
 class Directory(FsObject):
diff --git a/fileformats/generic/file.py b/fileformats/generic/file.py
index 16fd87e..22e5b6e 100644
--- a/fileformats/generic/file.py
+++ b/fileformats/generic/file.py
@@ -125,7 +125,7 @@ def actual_ext(self) -> str:
                 "(i.e. matches the None extension)"
             )
         # Return the longest matching extension, useful for optional extensions
-        return sorted(matching, key=len)[-1]
+        return sorted(matching, key=len)[-1]  # type: ignore[no-any-return]
 
     @property
     def stem(self) -> str:
diff --git a/fileformats/image/raster.py b/fileformats/image/raster.py
index 295691f..46e998a 100644
--- a/fileformats/image/raster.py
+++ b/fileformats/image/raster.py
@@ -1,5 +1,5 @@
 from pathlib import Path
-from typing_extensions import Self, TypeAlias
+from fileformats.core.typing import Self, TypeAlias
 import typing as ty
 from fileformats.core.mixin import WithMagicNumber
 from fileformats.core import extra