Index: src/wp-admin/includes/class-walker-nav-menu-edit.php
===================================================================
--- src/wp-admin/includes/class-walker-nav-menu-edit.php	(revision 39557)
+++ src/wp-admin/includes/class-walker-nav-menu-edit.php	(working copy)
@@ -196,7 +196,18 @@
 						<span class="description"><?php _e('The description will be displayed in the menu if the current theme supports it.'); ?></span>
 					</label>
 				</p>
-
+				<?php
+				/**
+				 * Let users add custom menu settings without overwriting the whole walker.
+				 *
+				 * @since 4.7.1
+				 *
+				 * @param object $item    Menu item data object.
+				 * @param int    $depth   Depth of menu item. Used for padding.
+				 * @param array  $classes Classnames for the menu item.
+				 */
+				do_action( 'admin_nav_menu_item_below_settings', $item, $depth, $classes );
+				?>
 				<fieldset class="field-move hide-if-no-js description description-wide">
 					<span class="field-move-visual-label" aria-hidden="true"><?php _e( 'Move' ); ?></span>
 					<button type="button" class="button-link menus-move menus-move-up" data-dir="up"><?php _e( 'Up one' ); ?></button>