Carbon_Fields\Walker\Nav_Menu_Edit_Walker::start_el PHP Метод

    public function start_el(&$output, $item, $depth = 0, $args = array(), $id = 0)
    {
        parent::start_el($output, $item, $depth, $args, $id);
        $flag = '<!--CarbonFields-->';
        ob_start();
        do_action('crb_print_carbon_container_nav_menu_fields_html', $item, $output, $depth, $args, $id);
        echo $flag;
        $fields = ob_get_clean();
        $marker = '<p class="field-move hide-if-no-js description description-wide">';
        $output = preg_replace('~(?<!' . preg_quote($flag, '~') . ')' . preg_quote($marker, '~') . '~', $fields . $marker, $output);
    }