tml_admin_nav_menu_meta_box()

function tml_admin_nav_menu_meta_box() {
    global $_nav_menu_placeholder, $nav_menu_selected_id;

    // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited -- mirrors WP core's own placeholder-ID counter pattern in wp-admin/includes/nav-menu.php.
    $_nav_menu_placeholder = 0 > $_nav_menu_placeholder ? $_nav_menu_placeholder - 1 : -1;

    $actions = wp_list_filter(
        tml_get_actions(),
        array(
            'show_in_nav_menus' => true,
        )
    );
    ?>

    <div id="tml-action" class="posttypediv">
        <div class="tabs-panel tabs-panel-active">
            <ul class="categorychecklist form-no-clear">
                <?php
                echo walk_nav_menu_tree(
                    array_map( 'wp_setup_nav_menu_item', $actions ),
                    0,
                    (object) array(
                        'walker' => new Walker_Nav_Menu_Checklist(),
                    )
                );
                ?>
            </ul>
        </div>
        <p class="button-controls wp-clearfix">
            <span class="add-to-menu">
                <input type="submit"<?php wp_nav_menu_disabled_check( $nav_menu_selected_id ); ?> class="button submit-add-to-menu right" value="<?php esc_attr_e( 'Add to Menu' ); /* phpcs:ignore WordPress.WP.I18n.MissingArgDomain -- reusing WP core's translated "Add to Menu" string (see wp-admin/includes/nav-menu.php), not a TML-specific string. */ ?>" name="add-tml-action-menu-item" id="submit-tml-action" />
                <span class="spinner"></span>
            </span>
        </p>
    </div>

    <?php
}

View src/admin/functions.php, line 343 on GitHub