Ticket #27280: 27280.patch

src/wp-admin/includes/class-walker-nav-menu-edit.php

@@ -232 +232 @@
                         </div><!-- .menu-item-settings-->
                         <ul class="menu-item-transport"></ul>
                 <?php
-                $output .= ob_get_clean();
+                $item_output = ob_get_clean();
+
+                /**
+                 * Filter a menu item's starting output.
+                 *
+                 * The menu item's starting output only includes `$args->before`, the opening `<a>`,
+                 * the menu item's title, the closing `</a>`, and `$args->after`. Currently, there is
+                 * no filter for modifying the opening and closing `<li>` for a menu item.
+                 *
+                 * @since 4.4.0
+                 *
+                 * @param string $item_output The menu item's starting HTML output.
+                 * @param object $item        Menu item data object.
+                 * @param int    $depth       Depth of menu item. Used for padding.
+                 * @param array  $args        An array of {@see wp_nav_menu()} arguments.
+                 */
+                $output .= apply_filters( 'walker_nav_menu_edit_start_el', $item_output, $item, $depth, $args );
         }
 
 } // Walker_Nav_Menu_Edit