Source

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

public function create_item_permissions_check( $request ) {
		$id = $request->get_param( 'id' );

		if ( empty( $id ) ) {
			return new WP_Error(
				'rest_post_invalid_id',
				__( 'Invalid item ID.' ),
				array( 'status' => 404 )
			);
		}

		return $this->parent_controller->update_item_permissions_check( $request );
	}