WordPress at a glance
function is not described

_wp_delete_post_menu_item() WP 3.0.0

Callback for handling a menu item when its original object is deleted.

No Hooks.

Return

Nothing (null).

Usage

_wp_delete_post_menu_item( $object_id );
$object_id(int)
The ID of the original object being trashed.
Default: 0

Code of wp delete post menu item: wp-includes/nav-menu.php WP 5.2.1

<?php
function _wp_delete_post_menu_item( $object_id = 0 ) {
	$object_id = (int) $object_id;

	$menu_item_ids = wp_get_associated_nav_menu_items( $object_id, 'post_type' );

	foreach ( (array) $menu_item_ids as $menu_item_id ) {
		wp_delete_post( $menu_item_id, true );
	}
}