diff --git a/src/wp-includes/class-walker-nav-menu.php b/src/wp-includes/class-walker-nav-menu.php
new file mode 100644
index 0000000000..43eaa91c66
--- /dev/null
+++ b/src/wp-includes/class-walker-nav-menu.php
@@ -0,0 +1,222 @@
+ 'menu_item_parent', 'id' => 'db_id' );
+
+ /**
+ * Starts the list before the elements are added.
+ *
+ * @since 3.0.0
+ *
+ * @see Walker::start_lvl()
+ *
+ * @param string $output Passed by reference. Used to append additional content.
+ * @param int $depth Depth of menu item. Used for padding.
+ * @param array $args An array of wp_nav_menu() arguments.
+ */
+ public function start_lvl( &$output, $depth = 0, $args = array() ) {
+ $indent = str_repeat("\t", $depth);
+ $output .= "\n$indent
\n";
+ }
+
+ /**
+ * Starts the element output.
+ *
+ * @since 3.0.0
+ * @since 4.4.0 The {@see 'nav_menu_item_args'} filter was added.
+ *
+ * @see Walker::start_el()
+ *
+ * @param string $output Passed by reference. Used to append additional content.
+ * @param object $item Menu item data object.
+ * @param int $depth Depth of menu item. Used for padding.
+ * @param array $args An array of wp_nav_menu() arguments.
+ * @param int $id Current item ID.
+ */
+ public function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
+ $indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';
+
+ $classes = empty( $item->classes ) ? array() : (array) $item->classes;
+ $classes[] = 'menu-item-' . $item->ID;
+
+ /**
+ * Filters the arguments for a single nav menu item.
+ *
+ * @since 4.4.0
+ *
+ * @param array $args An array of arguments.
+ * @param object $item Menu item data object.
+ * @param int $depth Depth of menu item. Used for padding.
+ */
+ $args = apply_filters( 'nav_menu_item_args', $args, $item, $depth );
+
+ /**
+ * Filters the CSS class(es) applied to a menu item's list item element.
+ *
+ * @since 3.0.0
+ * @since 4.1.0 The `$depth` parameter was added.
+ *
+ * @param array $classes The CSS classes that are applied to the menu item's `` element.
+ * @param object $item The current menu item.
+ * @param array $args An array of wp_nav_menu() arguments.
+ * @param int $depth Depth of menu item. Used for padding.
+ */
+ $class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args, $depth ) );
+ $class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';
+
+ /**
+ * Filters the ID applied to a menu item's list item element.
+ *
+ * @since 3.0.1
+ * @since 4.1.0 The `$depth` parameter was added.
+ *
+ * @param string $menu_id The ID that is applied to the menu item's `` element.
+ * @param object $item The current menu item.
+ * @param array $args An array of wp_nav_menu() arguments.
+ * @param int $depth Depth of menu item. Used for padding.
+ */
+ $id = apply_filters( 'nav_menu_item_id', 'menu-item-'. $item->ID, $item, $args, $depth );
+ $id = $id ? ' id="' . esc_attr( $id ) . '"' : '';
+
+ $output .= $indent . '';
+
+ $atts = array();
+ $atts['title'] = ! empty( $item->attr_title ) ? $item->attr_title : '';
+ $atts['target'] = ! empty( $item->target ) ? $item->target : '';
+ $atts['rel'] = ! empty( $item->xfn ) ? $item->xfn : '';
+ $atts['href'] = ! empty( $item->url ) ? $item->url : '';
+
+ /**
+ * Filters the HTML attributes applied to a menu item's anchor element.
+ *
+ * @since 3.6.0
+ * @since 4.1.0 The `$depth` parameter was added.
+ *
+ * @param array $atts {
+ * The HTML attributes applied to the menu item's `` element, empty strings are ignored.
+ *
+ * @type string $title Title attribute.
+ * @type string $target Target attribute.
+ * @type string $rel The rel attribute.
+ * @type string $href The href attribute.
+ * }
+ * @param object $item The current menu item.
+ * @param array $args An array of wp_nav_menu() arguments.
+ * @param int $depth Depth of menu item. Used for padding.
+ */
+ $atts = apply_filters( 'nav_menu_link_attributes', $atts, $item, $args, $depth );
+
+ $attributes = '';
+ foreach ( $atts as $attr => $value ) {
+ if ( ! empty( $value ) ) {
+ $value = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
+ $attributes .= ' ' . $attr . '="' . $value . '"';
+ }
+ }
+
+ /** This filter is documented in wp-includes/post-template.php */
+ $title = apply_filters( 'the_title', $item->title, $item->ID );
+
+ /**
+ * Filters a menu item's title.
+ *
+ * @since 4.4.0
+ *
+ * @param string $title The menu item's title.
+ * @param object $item The current menu item.
+ * @param array $args An array of wp_nav_menu() arguments.
+ * @param int $depth Depth of menu item. Used for padding.
+ */
+ $title = apply_filters( 'nav_menu_item_title', $title, $item, $args, $depth );
+
+ $item_output = $args->before;
+ $item_output .= '';
+ $item_output .= $args->link_before . $title . $args->link_after;
+ $item_output .= '';
+ $item_output .= $args->after;
+
+ /**
+ * Filters a menu item's starting output.
+ *
+ * The menu item's starting output only includes `$args->before`, the opening ``,
+ * the menu item's title, the closing ``, and `$args->after`. Currently, there is
+ * no filter for modifying the opening and closing `` for a menu item.
+ *
+ * @since 3.0.0
+ *
+ * @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 wp_nav_menu() arguments.
+ */
+ $output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
+ }
+
+ /**
+ * Ends the element output, if needed.
+ *
+ * @since 3.0.0
+ *
+ * @see Walker::end_el()
+ *
+ * @param string $output Passed by reference. Used to append additional content.
+ * @param object $item Page data object. Not used.
+ * @param int $depth Depth of page. Not Used.
+ * @param array $args An array of wp_nav_menu() arguments.
+ */
+ public function end_el( &$output, $item, $depth = 0, $args = array() ) {
+ $output .= "\n";
+ }
+
+} // Walker_Nav_Menu
diff --git a/src/wp-includes/nav-menu-template.php b/src/wp-includes/nav-menu-template.php
index f00d1fad64..62a66d39ae 100644
--- a/src/wp-includes/nav-menu-template.php
+++ b/src/wp-includes/nav-menu-template.php
@@ -1,224 +1,14 @@
'menu_item_parent', 'id' => 'db_id' );
-
- /**
- * Starts the list before the elements are added.
- *
- * @since 3.0.0
- *
- * @see Walker::start_lvl()
- *
- * @param string $output Passed by reference. Used to append additional content.
- * @param int $depth Depth of menu item. Used for padding.
- * @param array $args An array of wp_nav_menu() arguments.
- */
- public function start_lvl( &$output, $depth = 0, $args = array() ) {
- $indent = str_repeat("\t", $depth);
- $output .= "\n$indent\n";
- }
-
- /**
- * Starts the element output.
- *
- * @since 3.0.0
- * @since 4.4.0 The {@see 'nav_menu_item_args'} filter was added.
- *
- * @see Walker::start_el()
- *
- * @param string $output Passed by reference. Used to append additional content.
- * @param object $item Menu item data object.
- * @param int $depth Depth of menu item. Used for padding.
- * @param array $args An array of wp_nav_menu() arguments.
- * @param int $id Current item ID.
- */
- public function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
- $indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';
-
- $classes = empty( $item->classes ) ? array() : (array) $item->classes;
- $classes[] = 'menu-item-' . $item->ID;
-
- /**
- * Filters the arguments for a single nav menu item.
- *
- * @since 4.4.0
- *
- * @param array $args An array of arguments.
- * @param object $item Menu item data object.
- * @param int $depth Depth of menu item. Used for padding.
- */
- $args = apply_filters( 'nav_menu_item_args', $args, $item, $depth );
-
- /**
- * Filters the CSS class(es) applied to a menu item's list item element.
- *
- * @since 3.0.0
- * @since 4.1.0 The `$depth` parameter was added.
- *
- * @param array $classes The CSS classes that are applied to the menu item's `` element.
- * @param object $item The current menu item.
- * @param array $args An array of wp_nav_menu() arguments.
- * @param int $depth Depth of menu item. Used for padding.
- */
- $class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args, $depth ) );
- $class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';
-
- /**
- * Filters the ID applied to a menu item's list item element.
- *
- * @since 3.0.1
- * @since 4.1.0 The `$depth` parameter was added.
- *
- * @param string $menu_id The ID that is applied to the menu item's `` element.
- * @param object $item The current menu item.
- * @param array $args An array of wp_nav_menu() arguments.
- * @param int $depth Depth of menu item. Used for padding.
- */
- $id = apply_filters( 'nav_menu_item_id', 'menu-item-'. $item->ID, $item, $args, $depth );
- $id = $id ? ' id="' . esc_attr( $id ) . '"' : '';
-
- $output .= $indent . '';
-
- $atts = array();
- $atts['title'] = ! empty( $item->attr_title ) ? $item->attr_title : '';
- $atts['target'] = ! empty( $item->target ) ? $item->target : '';
- $atts['rel'] = ! empty( $item->xfn ) ? $item->xfn : '';
- $atts['href'] = ! empty( $item->url ) ? $item->url : '';
-
- /**
- * Filters the HTML attributes applied to a menu item's anchor element.
- *
- * @since 3.6.0
- * @since 4.1.0 The `$depth` parameter was added.
- *
- * @param array $atts {
- * The HTML attributes applied to the menu item's `` element, empty strings are ignored.
- *
- * @type string $title Title attribute.
- * @type string $target Target attribute.
- * @type string $rel The rel attribute.
- * @type string $href The href attribute.
- * }
- * @param object $item The current menu item.
- * @param array $args An array of wp_nav_menu() arguments.
- * @param int $depth Depth of menu item. Used for padding.
- */
- $atts = apply_filters( 'nav_menu_link_attributes', $atts, $item, $args, $depth );
-
- $attributes = '';
- foreach ( $atts as $attr => $value ) {
- if ( ! empty( $value ) ) {
- $value = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
- $attributes .= ' ' . $attr . '="' . $value . '"';
- }
- }
-
- /** This filter is documented in wp-includes/post-template.php */
- $title = apply_filters( 'the_title', $item->title, $item->ID );
-
- /**
- * Filters a menu item's title.
- *
- * @since 4.4.0
- *
- * @param string $title The menu item's title.
- * @param object $item The current menu item.
- * @param array $args An array of wp_nav_menu() arguments.
- * @param int $depth Depth of menu item. Used for padding.
- */
- $title = apply_filters( 'nav_menu_item_title', $title, $item, $args, $depth );
-
- $item_output = $args->before;
- $item_output .= '';
- $item_output .= $args->link_before . $title . $args->link_after;
- $item_output .= '';
- $item_output .= $args->after;
-
- /**
- * Filters a menu item's starting output.
- *
- * The menu item's starting output only includes `$args->before`, the opening ``,
- * the menu item's title, the closing ``, and `$args->after`. Currently, there is
- * no filter for modifying the opening and closing `` for a menu item.
- *
- * @since 3.0.0
- *
- * @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 wp_nav_menu() arguments.
- */
- $output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
- }
-
- /**
- * Ends the element output, if needed.
- *
- * @since 3.0.0
- *
- * @see Walker::end_el()
- *
- * @param string $output Passed by reference. Used to append additional content.
- * @param object $item Page data object. Not used.
- * @param int $depth Depth of page. Not Used.
- * @param array $args An array of wp_nav_menu() arguments.
- */
- public function end_el( &$output, $item, $depth = 0, $args = array() ) {
- $output .= "\n";
- }
-
-} // Walker_Nav_Menu
+/** Walker_Nav_Menu class */
+require_once ABSPATH . WPINC . '/class-walker-nav-menu.php';
/**
* Displays a navigation menu.