Source

File: wp-includes/widgets/class-wp-nav-menu-widget.php

public function __construct() {
		$widget_ops = array(
			'description'                 => __( 'Add a navigation menu to your sidebar.' ),
			'customize_selective_refresh' => true,
		);
		parent::__construct( 'nav_menu', __( 'Navigation Menu' ), $widget_ops );
	}