WP_REST_Themes_Controller::get_item_schema

				$support = get_theme_support( $feature );

				if ( isset( $config['show_in_rest']['prepare_callback'] ) ) {
					$prepare = $config['show_in_rest']['prepare_callback'];
				} else {
					$prepare = array( $this, 'prepare_theme_support' );
				}

				$prepared = $prepare( $support, $config, $feature, $request );

				if ( is_wp_error( $prepared ) ) {
					continue;
				}

				$data['theme_supports'][ $name ] = $prepared;
			}
		}

		$data = $this->add_additional_fields_to_object( $data, $request );

		// Wrap the data in a response object.
		$response = rest_ensure_response( $data );

		/**
		 * Filters theme data returned from the REST API.
		 *
		 * @since 5.0.0
		 *
		 * @param WP_REST_Response $response The response object.
		 * @param WP_Theme         $theme    Theme object used to create response.
		 * @param WP_REST_Request  $request  Request object.
		 */
		return apply_filters( 'rest_prepare_theme', $response, $theme, $request );
	}

	/**
	 * Prepares the theme support value for inclusion in the REST API response.
	 *
	 * @since 5.5.0
	 *
	 * @param mixed           $support The raw value from get_theme_support().
	 * @param array           $args    The feature's registration args.
	 * @param string          $feature The feature name.
	 * @param WP_REST_Request $request The request object.
	 * @return mixed The prepared support value.
	 */
	protected function prepare_theme_support( $support, $args, $feature, $request ) {
		$schema = $args['show_in_rest']['schema'];

		if ( 'boolean' === $schema['type'] ) {
			return true;
		}

		if ( is_array( $support ) && ! $args['variadic'] ) {
			$support = $support[0];
		}

		return rest_sanitize_value_from_schema( $support, $schema );
	}

	/**
	 * Retrieves the theme's schema, conforming to JSON Schema.
	 *
	 * @since 5.0.0
	 *
	 * @return array Item schema data.
	 */
	public function get_item_schema() {
		if ( $this->schema ) {
			return $this->add_additional_fields_schema( $this->schema );
		}

		$schema = array(
			'$schema'    => 'http://json-schema.org/draft-04/schema#',
			'title'      => 'theme',
			'type'       => 'object',
			'properties' => array(
				'stylesheet'     => array(
					'description' => __( 'The theme\'s stylesheet. This uniquely identifies the theme.' ),
					'type'        => 'string',
					'readonly'    => true,
				),
				'template'       => array(
					'description' => __( 'The theme\'s template. If this is a child theme, this refers to the parent theme, otherwise this is the same as the theme\'s stylesheet.' ),
					'type'        => 'string',
					'readonly'    => true,
				),
				'author'         => array(
					'description' => __( 'The theme author.' ),
					'type'        => 'object',
					'readonly'    => true,
					'properties'  => array(
						'raw'      => array(
							'description' => __( 'The theme author\'s name, as found in the theme header.' ),
							'type'        => 'string',
						),
						'rendered' => array(
							'description' => __( 'HTML for the theme author, transformed for display.' ),
							'type'        => 'string',
						),
					),
				),
				'author_uri'     => array(
					'description' => __( 'The website of the theme author.' ),
					'type'        => 'object',
					'readonly'    => true,
					'properties'  => array(
						'raw'      => array(
							'description' => __( 'The website of the theme author, as found in the theme header.' ),
							'type'        => 'string',
							'format'      => 'uri',
						),
						'rendered' => array(
							'description' => __( 'The website of the theme author, transformed for display.' ),
							'type'        => 'string',
							'format'      => 'uri',
						),
					),
				),
				'description'    => array(
					'description' => __( 'A description of the theme.' ),
					'type'        => 'object',
					'readonly'    => true,
					'properties'  => array(
						'raw'      => array(
							'description' => __( 'The theme description, as found in the theme header.' ),
							'type'        => 'string',
						),
						'rendered' => array(
							'description' => __( 'The theme description, transformed for display.' ),
							'type'        => 'string',
						),
					),
				),
				'name'           => array(
					'description' => __( 'The name of the theme.' ),
					'type'        => 'object',
					'readonly'    => true,
					'properties'  => array(
						'raw'      => array(
							'description' => __( 'The theme name, as found in the theme header.' ),
							'type'        => 'string',
						),
						'rendered' => array(
							'description' => __( 'The theme name, transformed for display.' ),
							'type'        => 'string',
						),
					),
				),
				'requires_php'   => array(
					'description' => __( 'The minimum PHP version required for the theme to work.' ),
					'type'        => 'string',
					'readonly'    => true,
				),
				'requires_wp'    => array(
					'description' => __( 'The minimum WordPress version required for the theme to work.' ),
					'type'        => 'string',
					'readonly'    => true,
				),
				'screenshot'     => array(
					'description' => __( 'The theme\'s screenshot URL.' ),
					'type'        => 'string',
					'format'      => 'uri',
					'readonly'    => true,
				),
				'tags'           => array(
					'description' => __( 'Tags indicating styles and features of the theme.' ),
					'type'        => 'object',
					'readonly'    => true,
					'properties'  => array(
						'raw'      => array(
							'description' => __( 'The theme tags, as found in the theme header.' ),
							'type'        => 'array',
							'items'       => array(
								'type' => 'string',
							),
						),
						'rendered' => array(
							'description' => __( 'The theme tags, transformed for display.' ),
							'type'        => 'string',
						),
					),
				),
				'textdomain'     => array(
					'description' => __( 'The theme\'s text domain.' ),
					'type'        => 'string',
					'readonly'    => true,
				),
				'theme_supports' => array(
					'description' => __( 'Features supported by this theme.' ),
					'type'        => 'object',
					'readonly'    => true,
					'properties'  => array(),
				),
				'theme_uri'      => array(
					'description' => __( 'The URI of the theme\'s webpage.' ),
					'type'        => 'object',
					'readonly'    => true,
					'properties'  => array(
						'raw'      => array(
							'description' => __( 'The URI of the theme\'s webpage, as found in the theme header.' ),
							'type'        => 'string',
							'format'      => 'uri',
						),
						'rendered' => array(
							'description' => __( 'The URI of the theme\'s webpage, transformed for display.' ),
							'type'        => 'string',
							'format'      => 'uri',
						),
					),
				),
				'version'        => array(
					'description' => __( 'The theme\'s current version.' ),
					'type'        => 'string',
					'readonly'    => true,
				),
			),
		);

		foreach ( get_registered_theme_features() as $feature => $config ) {
			if ( ! is_array( $config['show_in_rest'] ) ) {
				continue;
			}

			$name = $config['show_in_rest']['name'];

			$schema['properties']['theme_supports']['properties'][ $name ] = $config['show_in_rest']['schema'];
		}

		$this->schema = $schema;

		return $this->add_additional_fields_schema( $this->schema );
	}

	/**
	 * Retrieves the search params for the themes collection.
	 *
	 * @since 5.0.0
	 *
	 * @return array Collection parameters.
	 */
	public function get_collection_params() {
		$query_params = parent::get_collection_params();

		$query_params['status'] = array(
			'description'       => __( 'Limit result set to themes assigned one or more statuses.' ),
			'type'              => 'array',
			'items'             => array(
				'enum' => array( 'active' ),
				'type' => 'string',
			),
			'required'          => true,
			'sanitize_callback' => array( $this, 'sanitize_theme_status' ),
		);

		/**
		 * Filter collection parameters for the themes controller.
		 *
		 * @since 5.0.0
		 *
		 * @param array $query_params JSON Schema-formatted collection parameters.
		 */
		return apply_filters( 'rest_themes_collection_params', $query_params );
	}

	/**
	 * Sanitizes and validates the list of theme status.
	 *
	 * @since 5.0.0
	 *
	 * @param string|array    $statuses  One or more theme statuses.
	 * @param WP_REST_Request $request   Full details about the request.
	 * @param string          $parameter Additional parameter to pass to validation.
	 * @return array|WP_Error A list of valid statuses, otherwise WP_Error object.
	 */
	public function sanitize_theme_status( $statuses, $request, $parameter ) {
		$statuses = wp_parse_slug_list( $statuses );

		foreach ( $statuses as $status ) {
			$result = rest_validate_request_arg( $status, $request, $parameter );

			if ( is_wp_error( $result ) ) {