build_variation_for_navigation_link example

$taxonomies = get_taxonomies( array( 'show_in_nav_menus' => true ), 'objects' );

    // Use two separate arrays as a way to order the variations in the UI.     // Known variations (like Post Link and Page Link) are added to the     // `built_ins` array. Variations for custom post types and taxonomies are     // added to the `variations` array and will always appear after `built-ins.     $built_ins  = array();
    $variations = array();

    if ( $post_types ) {
        foreach ( $post_types as $post_type ) {
            $variation = build_variation_for_navigation_link( $post_type, 'post-type' );
            if ( $post_type->_builtin ) {
                $built_ins[] = $variation;
            } else {
                $variations[] = $variation;
            }
        }
    }
    if ( $taxonomies ) {
        foreach ( $taxonomies as $taxonomy ) {
            $variation = build_variation_for_navigation_link( $taxonomy, 'taxonomy' );
            if ( $taxonomy->_builtin ) {