diff --git a/docs/reference-guides/block-api/block-patterns.md b/docs/reference-guides/block-api/block-patterns.md
index 68e47d50942372..a1da09d63a6c99 100644
--- a/docs/reference-guides/block-api/block-patterns.md
+++ b/docs/reference-guides/block-api/block-patterns.md
@@ -36,6 +36,7 @@ The properties available for block patterns are:
 -   `postTypes` (optional): An array of post types that the pattern is restricted to be used with. The pattern will only be available when editing one of the post types passed on the array, for all the other post types the pattern is not available at all.
 -   `templateTypes` (optional): An array of template types where the pattern makes sense e.g: '404' if the pattern is for a 404 page, single-post if the pattern is for showing a single post.
 -   `inserter` (optional): By default, all patterns will appear in the inserter. To hide a pattern so that it can only be inserted programmatically, set the `inserter` to `false`.
+-   `source` (optional): A string that denotes the source of the pattern. For a plugin registering a pattern, pass the string 'plugin'. For a theme, pass the string 'theme'.
 
 The following code sample registers a block pattern named 'my-plugin/my-awesome-pattern':
 
diff --git a/lib/compat/wordpress-6.2/block-patterns.php b/lib/compat/wordpress-6.2/block-patterns.php
index 2112a8c2c890f1..12b19bdf4c54ea 100644
--- a/lib/compat/wordpress-6.2/block-patterns.php
+++ b/lib/compat/wordpress-6.2/block-patterns.php
@@ -331,128 +331,3 @@ function gutenberg_normalize_remote_pattern( $pattern ) {
 
 	return (array) $pattern;
 }
-
-/**
- * Register Core's official patterns from wordpress.org/patterns.
- *
- * @since 5.8.0
- * @since 5.9.0 The $current_screen argument was removed.
- * @since 6.2.0 Normalize the pattern from the API (snake_case) to the format expected by `register_block_pattern` (camelCase).
- *
- * @param WP_Screen $deprecated Unused. Formerly the screen that the current request was triggered from.
- */
-function gutenberg_load_remote_block_patterns( $deprecated = null ) {
-	if ( ! empty( $deprecated ) ) {
-		_deprecated_argument( __FUNCTION__, '5.9.0' );
-		$current_screen = $deprecated;
-		if ( ! $current_screen->is_block_editor ) {
-			return;
-		}
-	}
-
-	$supports_core_patterns = get_theme_support( 'core-block-patterns' );
-
-	/**
-	 * Filter to disable remote block patterns.
-	 *
-	 * @since 5.8.0
-	 *
-	 * @param bool $should_load_remote
-	 */
-	$should_load_remote = apply_filters( 'should_load_remote_block_patterns', true );
-
-	if ( $supports_core_patterns && $should_load_remote ) {
-		$request         = new WP_REST_Request( 'GET', '/wp/v2/pattern-directory/patterns' );
-		$core_keyword_id = 11; // 11 is the ID for "core".
-		$request->set_param( 'keyword', $core_keyword_id );
-		$response = rest_do_request( $request );
-		if ( $response->is_error() ) {
-			return;
-		}
-		$patterns = $response->get_data();
-
-		foreach ( $patterns as $pattern ) {
-			$normalized_pattern = gutenberg_normalize_remote_pattern( $pattern );
-			$pattern_name       = 'core/' . sanitize_title( $normalized_pattern['title'] );
-			register_block_pattern( $pattern_name, (array) $normalized_pattern );
-		}
-	}
-}
-
-/**
- * Register `Featured` (category) patterns from wordpress.org/patterns.
- *
- * @since 5.9.0
- * @since 6.2.0 Normalize the pattern from the API (snake_case) to the format expected by `register_block_pattern` (camelCase).
- */
-function gutenberg_load_remote_featured_patterns() {
-	$supports_core_patterns = get_theme_support( 'core-block-patterns' );
-
-	/** This filter is documented in wp-includes/block-patterns.php */
-	$should_load_remote = apply_filters( 'should_load_remote_block_patterns', true );
-
-	if ( ! $should_load_remote || ! $supports_core_patterns ) {
-		return;
-	}
-
-	$request         = new WP_REST_Request( 'GET', '/wp/v2/pattern-directory/patterns' );
-	$featured_cat_id = 26; // This is the `Featured` category id from pattern directory.
-	$request->set_param( 'category', $featured_cat_id );
-	$response = rest_do_request( $request );
-	if ( $response->is_error() ) {
-		return;
-	}
-	$patterns = $response->get_data();
-	$registry = WP_Block_Patterns_Registry::get_instance();
-	foreach ( $patterns as $pattern ) {
-		$normalized_pattern = gutenberg_normalize_remote_pattern( $pattern );
-		$pattern_name       = sanitize_title( $normalized_pattern['title'] );
-		// Some patterns might be already registered as core patterns with the `core` prefix.
-		$is_registered = $registry->is_registered( $pattern_name ) || $registry->is_registered( "core/$pattern_name" );
-		if ( ! $is_registered ) {
-			register_block_pattern( $pattern_name, (array) $normalized_pattern );
-		}
-	}
-}
-
-/**
- * Registers patterns from Pattern Directory provided by a theme's
- * `theme.json` file.
- *
- * @since 6.0.0
- * @since 6.2.0 Normalize the pattern from the API (snake_case) to the format expected by `register_block_pattern` (camelCase).
- * @access private
- */
-function gutenberg_register_remote_theme_patterns() {
-	/** This filter is documented in wp-includes/block-patterns.php */
-	if ( ! apply_filters( 'should_load_remote_block_patterns', true ) ) {
-		return;
-	}
-
-	if ( ! wp_theme_has_theme_json() ) {
-		return;
-	}
-
-	$pattern_settings = gutenberg_get_remote_theme_patterns();
-	if ( empty( $pattern_settings ) ) {
-		return;
-	}
-
-	$request         = new WP_REST_Request( 'GET', '/wp/v2/pattern-directory/patterns' );
-	$request['slug'] = $pattern_settings;
-	$response        = rest_do_request( $request );
-	if ( $response->is_error() ) {
-		return;
-	}
-	$patterns          = $response->get_data();
-	$patterns_registry = WP_Block_Patterns_Registry::get_instance();
-	foreach ( $patterns as $pattern ) {
-		$normalized_pattern = gutenberg_normalize_remote_pattern( $pattern );
-		$pattern_name       = sanitize_title( $normalized_pattern['title'] );
-		// Some patterns might be already registered as core patterns with the `core` prefix.
-		$is_registered = $patterns_registry->is_registered( $pattern_name ) || $patterns_registry->is_registered( "core/$pattern_name" );
-		if ( ! $is_registered ) {
-			register_block_pattern( $pattern_name, (array) $normalized_pattern );
-		}
-	}
-}
diff --git a/lib/compat/wordpress-6.2/rest-api.php b/lib/compat/wordpress-6.2/rest-api.php
index b648ba9bae015e..c0f098fa6893ac 100644
--- a/lib/compat/wordpress-6.2/rest-api.php
+++ b/lib/compat/wordpress-6.2/rest-api.php
@@ -14,15 +14,6 @@ function gutenberg_register_rest_block_pattern_categories() {
 }
 add_action( 'rest_api_init', 'gutenberg_register_rest_block_pattern_categories' );
 
-/**
- * Registers the block patterns REST API routes.
- */
-function gutenberg_register_rest_block_patterns() {
-	$block_patterns = new Gutenberg_REST_Block_Patterns_Controller_6_2();
-	$block_patterns->register_routes();
-}
-add_action( 'rest_api_init', 'gutenberg_register_rest_block_patterns' );
-
 /**
  * Add extra collection params to pattern directory requests.
  *
diff --git a/lib/compat/wordpress-6.3/block-patterns.php b/lib/compat/wordpress-6.3/block-patterns.php
new file mode 100644
index 00000000000000..b620317f86966d
--- /dev/null
+++ b/lib/compat/wordpress-6.3/block-patterns.php
@@ -0,0 +1,165 @@
+<?php
+/**
+ * Overrides Core's wp-includes/block-patterns.php to add category descriptions for WP 6.3.
+ *
+ * @package gutenberg
+ */
+
+/**
+ * Registers the block pattern sources.
+ *
+ * @since 6.3.0 Added source to core block patterns.
+ */
+function gutenberg_register_core_block_patterns_and_categories() {
+	$should_register_core_patterns = get_theme_support( 'core-block-patterns' );
+
+	if ( $should_register_core_patterns ) {
+		$core_block_patterns = array(
+			'query-standard-posts',
+			'query-medium-posts',
+			'query-small-posts',
+			'query-grid-posts',
+			'query-large-title-posts',
+			'query-offset-posts',
+			'social-links-shared-background-color',
+		);
+
+		foreach ( $core_block_patterns as $core_block_pattern ) {
+			$pattern           = require ABSPATH . WPINC . '/block-patterns/' . $core_block_pattern . '.php';
+			$pattern['source'] = 'core'; // Added in 6.3.0.
+			register_block_pattern( 'core/' . $core_block_pattern, $pattern );
+		}
+	}
+}
+add_action( 'init', 'gutenberg_register_core_block_patterns_and_categories' );
+
+/**
+ * Register Core's official patterns from wordpress.org/patterns.
+ *
+ * @since 5.8.0
+ * @since 5.9.0 The $current_screen argument was removed.
+ * @since 6.2.0 Normalize the pattern from the API (snake_case) to the format expected by `register_block_pattern` (camelCase).
+ * @since 6.3.0 Add 'pattern-directory/core' to the pattern's 'source'.
+ *
+ * @param WP_Screen $deprecated Unused. Formerly the screen that the current request was triggered from.
+ */
+function gutenberg_load_remote_block_patterns( $deprecated = null ) {
+	if ( ! empty( $deprecated ) ) {
+		_deprecated_argument( __FUNCTION__, '5.9.0' );
+		$current_screen = $deprecated;
+		if ( ! $current_screen->is_block_editor ) {
+			return;
+		}
+	}
+
+	$supports_core_patterns = get_theme_support( 'core-block-patterns' );
+
+	/**
+	 * Filter to disable remote block patterns.
+	 *
+	 * @since 5.8.0
+	 *
+	 * @param bool $should_load_remote
+	 */
+	$should_load_remote = apply_filters( 'should_load_remote_block_patterns', true );
+
+	if ( $supports_core_patterns && $should_load_remote ) {
+		$request         = new WP_REST_Request( 'GET', '/wp/v2/pattern-directory/patterns' );
+		$core_keyword_id = 11; // 11 is the ID for "core".
+		$request->set_param( 'keyword', $core_keyword_id );
+		$response = rest_do_request( $request );
+		if ( $response->is_error() ) {
+			return;
+		}
+		$patterns = $response->get_data();
+
+		foreach ( $patterns as $pattern ) {
+			$pattern['source']  = 'pattern-directory/core'; // Added in 6.3.0.
+			$normalized_pattern = gutenberg_normalize_remote_pattern( $pattern );
+			$pattern_name       = 'core/' . sanitize_title( $normalized_pattern['title'] );
+			register_block_pattern( $pattern_name, (array) $normalized_pattern );
+		}
+	}
+}
+
+/**
+ * Register `Featured` (category) patterns from wordpress.org/patterns.
+ *
+ * @since 5.9.0
+ * @since 6.2.0 Normalize the pattern from the API (snake_case) to the format expected by `register_block_pattern` (camelCase).
+ * @since 6.3.0 Add 'pattern-directory/featured' to the pattern's 'source'.
+ */
+function gutenberg_load_remote_featured_patterns() {
+	$supports_core_patterns = get_theme_support( 'core-block-patterns' );
+
+	/** This filter is documented in wp-includes/block-patterns.php */
+	$should_load_remote = apply_filters( 'should_load_remote_block_patterns', true );
+
+	if ( ! $should_load_remote || ! $supports_core_patterns ) {
+		return;
+	}
+
+	$request         = new WP_REST_Request( 'GET', '/wp/v2/pattern-directory/patterns' );
+	$featured_cat_id = 26; // This is the `Featured` category id from pattern directory.
+	$request->set_param( 'category', $featured_cat_id );
+	$response = rest_do_request( $request );
+	if ( $response->is_error() ) {
+		return;
+	}
+	$patterns = $response->get_data();
+	$registry = WP_Block_Patterns_Registry::get_instance();
+	foreach ( $patterns as $pattern ) {
+		$pattern['source']  = 'pattern-directory/featured'; // Added in 6.3.0.
+		$normalized_pattern = gutenberg_normalize_remote_pattern( $pattern );
+		$pattern_name       = sanitize_title( $normalized_pattern['title'] );
+		// Some patterns might be already registered as core patterns with the `core` prefix.
+		$is_registered = $registry->is_registered( $pattern_name ) || $registry->is_registered( "core/$pattern_name" );
+		if ( ! $is_registered ) {
+			register_block_pattern( $pattern_name, (array) $normalized_pattern );
+		}
+	}
+}
+
+/**
+ * Registers patterns from Pattern Directory provided by a theme's
+ * `theme.json` file.
+ *
+ * @since 6.0.0
+ * @since 6.2.0 Normalize the pattern from the API (snake_case) to the format expected by `register_block_pattern` (camelCase).
+ * @since 6.3.0 Add 'pattern-directory/theme' to the pattern's 'source'.
+ * @access private
+ */
+function gutenberg_register_remote_theme_patterns() {
+	/** This filter is documented in wp-includes/block-patterns.php */
+	if ( ! apply_filters( 'should_load_remote_block_patterns', true ) ) {
+		return;
+	}
+
+	if ( ! wp_theme_has_theme_json() ) {
+		return;
+	}
+
+	$pattern_settings = gutenberg_get_remote_theme_patterns();
+	if ( empty( $pattern_settings ) ) {
+		return;
+	}
+
+	$request         = new WP_REST_Request( 'GET', '/wp/v2/pattern-directory/patterns' );
+	$request['slug'] = $pattern_settings;
+	$response        = rest_do_request( $request );
+	if ( $response->is_error() ) {
+		return;
+	}
+	$patterns          = $response->get_data();
+	$patterns_registry = WP_Block_Patterns_Registry::get_instance();
+	foreach ( $patterns as $pattern ) {
+		$pattern['source']  = 'pattern-directory/theme'; // Added in 6.3.0.
+		$normalized_pattern = gutenberg_normalize_remote_pattern( $pattern );
+		$pattern_name       = sanitize_title( $normalized_pattern['title'] );
+		// Some patterns might be already registered as core patterns with the `core` prefix.
+		$is_registered = $patterns_registry->is_registered( $pattern_name ) || $patterns_registry->is_registered( "core/$pattern_name" );
+		if ( ! $is_registered ) {
+			register_block_pattern( $pattern_name, (array) $normalized_pattern );
+		}
+	}
+}
diff --git a/lib/compat/wordpress-6.3/class-gutenberg-rest-block-patterns-controller-6-3.php b/lib/compat/wordpress-6.3/class-gutenberg-rest-block-patterns-controller-6-3.php
new file mode 100644
index 00000000000000..036864bd8190fe
--- /dev/null
+++ b/lib/compat/wordpress-6.3/class-gutenberg-rest-block-patterns-controller-6-3.php
@@ -0,0 +1,155 @@
+<?php
+/**
+ * REST API: Gutenberg_REST_Block_Patterns_Controller_6_3 class
+ *
+ * @package    Gutenberg
+ * @subpackage REST_API
+ */
+
+/**
+ * Core class used to access block patterns via the REST API.
+ *
+ * @since 6.0.0
+ *
+ * @see WP_REST_Controller
+ */
+class Gutenberg_REST_Block_Patterns_Controller_6_3 extends Gutenberg_REST_Block_Patterns_Controller_6_2 {
+	/**
+	 * Prepare a raw block pattern before it gets output in a REST API response.
+	 *
+	 * @since 6.0.0
+	 * @since 6.3.0 Added `source` property.
+	 *
+	 * @param array           $item    Raw pattern as registered, before any changes.
+	 * @param WP_REST_Request $request Request object.
+	 * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.
+	 */
+	public function prepare_item_for_response( $item, $request ) {
+		$fields = $this->get_fields_for_response( $request );
+		$keys   = array(
+			'name'          => 'name',
+			'title'         => 'title',
+			'description'   => 'description',
+			'viewportWidth' => 'viewport_width',
+			'blockTypes'    => 'block_types',
+			'postTypes'     => 'post_types',
+			'categories'    => 'categories',
+			'keywords'      => 'keywords',
+			'content'       => 'content',
+			'inserter'      => 'inserter',
+			'templateTypes' => 'template_types',
+			'source'        => 'source',
+		);
+		$data   = array();
+		foreach ( $keys as $item_key => $rest_key ) {
+			if ( isset( $item[ $item_key ] ) && rest_is_field_included( $rest_key, $fields ) ) {
+				$data[ $rest_key ] = $item[ $item_key ];
+			}
+		}
+		$context = ! empty( $request['context'] ) ? $request['context'] : 'view';
+		$data    = $this->add_additional_fields_to_object( $data, $request );
+		$data    = $this->filter_response_by_context( $data, $context );
+		return rest_ensure_response( $data );
+	}
+
+	/**
+	 * Retrieves the block pattern schema, conforming to JSON Schema.
+	 *
+	 * @since 6.0.0
+	 * @since 6.1.0 Added `post_types` property.
+	 * @since 6.3.0 Added `source` property.
+	 *
+	 * @return array Item schema data.
+	 */
+	public function get_item_schema() {
+		$schema = array(
+			'$schema'    => 'http://json-schema.org/draft-04/schema#',
+			'title'      => 'block-pattern',
+			'type'       => 'object',
+			'properties' => array(
+				'name'           => array(
+					'description' => __( 'The pattern name.', 'gutenberg' ),
+					'type'        => 'string',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'title'          => array(
+					'description' => __( 'The pattern title, in human readable format.', 'gutenberg' ),
+					'type'        => 'string',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'description'    => array(
+					'description' => __( 'The pattern detailed description.', 'gutenberg' ),
+					'type'        => 'string',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'viewport_width' => array(
+					'description' => __( 'The pattern viewport width for inserter preview.', 'gutenberg' ),
+					'type'        => 'number',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'block_types'    => array(
+					'description' => __( 'Block types that the pattern is intended to be used with.', 'gutenberg' ),
+					'type'        => 'array',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'post_types'     => array(
+					'description' => __( 'An array of post types that the pattern is restricted to be used with.', 'gutenberg' ),
+					'type'        => 'array',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'categories'     => array(
+					'description' => __( 'The pattern category slugs.', 'gutenberg' ),
+					'type'        => 'array',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'keywords'       => array(
+					'description' => __( 'The pattern keywords.', 'gutenberg' ),
+					'type'        => 'array',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'template_types' => array(
+					'description' => __( 'An array of template types where the pattern fits.', 'gutenberg' ),
+					'type'        => 'array',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'content'        => array(
+					'description' => __( 'The pattern content.', 'gutenberg' ),
+					'type'        => 'string',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'inserter'       => array(
+					'description' => __( 'Determines whether the pattern is visible in inserter.', 'gutenberg' ),
+					'type'        => 'boolean',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'source'         => array(
+					'description' => __( 'Where the pattern comes from e.g. core', 'gutenberg' ),
+					'type'        => 'string',
+					'readonly'    => true,
+					'context'     => array( 'view', 'edit', 'embed' ),
+					'enum'        => array(
+						'core',
+						'plugin',
+						'theme',
+						'pattern-directory/core',
+						'pattern-directory/theme',
+						'pattern-directory/featured',
+					),
+				),
+			),
+		);
+
+		return $this->add_additional_fields_schema( $schema );
+	}
+}
diff --git a/lib/compat/wordpress-6.3/rest-api.php b/lib/compat/wordpress-6.3/rest-api.php
index a2dd66c5e922f8..ed6832c3b84119 100644
--- a/lib/compat/wordpress-6.3/rest-api.php
+++ b/lib/compat/wordpress-6.3/rest-api.php
@@ -101,3 +101,12 @@ function add_modified_wp_template_schema() {
 		);
 }
 add_filter( 'rest_api_init', 'add_modified_wp_template_schema' );
+
+/**
+ * Registers the block patterns REST API routes.
+ */
+function gutenberg_register_rest_block_patterns() {
+	$block_patterns = new Gutenberg_REST_Block_Patterns_Controller_6_3();
+	$block_patterns->register_routes();
+}
+add_action( 'rest_api_init', 'gutenberg_register_rest_block_patterns' );
diff --git a/lib/load.php b/lib/load.php
index afda5db277a52e..0fd23fc28f5133 100644
--- a/lib/load.php
+++ b/lib/load.php
@@ -44,6 +44,7 @@ function gutenberg_is_experiment_enabled( $name ) {
 	require_once __DIR__ . '/compat/wordpress-6.2/class-gutenberg-rest-global-styles-controller-6-2.php';
 
 	// WordPress 6.3 compat.
+	require_once __DIR__ . '/compat/wordpress-6.3/class-gutenberg-rest-block-patterns-controller-6-3.php';
 	require_once __DIR__ . '/compat/wordpress-6.3/class-gutenberg-rest-templates-controller-6-3.php';
 	require_once __DIR__ . '/compat/wordpress-6.3/class-gutenberg-rest-global-styles-controller-6-3.php';
 	require_once __DIR__ . '/compat/wordpress-6.3/class-gutenberg-rest-global-styles-revisions-controller-6-3.php';
@@ -52,6 +53,7 @@ function gutenberg_is_experiment_enabled( $name ) {
 	require_once __DIR__ . '/compat/wordpress-6.3/theme-previews.php';
 	require_once __DIR__ . '/compat/wordpress-6.3/navigation-block-preloading.php';
 	require_once __DIR__ . '/compat/wordpress-6.3/link-template.php';
+	require_once __DIR__ . '/compat/wordpress-6.3/block-patterns.php';
 
 	// Experimental.
 	if ( ! class_exists( 'WP_Rest_Customizer_Nonces' ) ) {