Source

File: wp-includes/rest-api/endpoints/class-wp-rest-themes-controller.php

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 );
	}