_register_widget_form_callback( int|string $id, string $name, callable $form_callback, array $options = array(), mixed $params )

640function _register_widget_form_callback( $id, $name, $form_callback, $options = array(), ...$params ) {641	global $wp_registered_widget_controls;642 643	$id = strtolower( $id );644 645	if ( empty( $form_callback ) ) {646		unset( $wp_registered_widget_controls[ $id ] );647		return;648	}649 650	if ( isset( $wp_registered_widget_controls[ $id ] ) && ! did_action( 'widgets_init' ) ) {651		return;652	}653 654	$defaults          = array(655		'width'  => 250,656		'height' => 200,657	);658	$options           = wp_parse_args( $options, $defaults );659	$options['width']  = (int) $options['width'];660	$options['height'] = (int) $options['height'];661 662	$widget = array(663		'name'     => $name,664		'id'       => $id,665		'callback' => $form_callback,666		'params'   => $params,667	);668	$widget = array_merge( $widget, $options );669 670	$wp_registered_widget_controls[ $id ] = $widget;671}