add new menu item to appearance Menus page

This adds a custom meta box:

if ( !class_exists('DM_Custom_MetaBox')) {
    class DM_Custom_MetaBox {
        public function add_nav_menu_meta_boxes() {
        	add_meta_box(
        		'custom-meta-box',
        		'Custom Meta Box',
        		array( $this, 'nav_menu_link'),
        		'nav-menus',
        		'side',
        		'low'
        	);
        }
        
        public function nav_menu_link() {
        	echo 'Custom Meta Box';
        }
    }
}

$custom_meta_box = new DM_Custom_MetaBox;

add_action('admin_init', array($custom_meta_box, 'add_nav_menu_meta_boxes'));

Thank you for your code example. Did not get it to work, but it helped. I did not realize that it was just another meta_box. I saw that you use ‘nav-menus’ so I was able to get a working start.
Thanks