wp-includes/customize/class-wp-customize-nav-menu-item-control.php:64JS/Underscore template for the control UI.
One hook fires while WP_Customize_Nav_Menu_Item_Control::content_template() runs, in this order:
Fires at the end of the form field template for nav menu items in the customizer.
public function content_template() { ?> <div class="menu-item-bar"> <div class="menu-item-handle"> <span class="item-type" aria-hidden="true">{{ data.item_type_label }}</span> <span class="item-title" aria-hidden="true"> <span class="spinner"></span> <span class="menu-item-title<# if ( ! data.title && ! data.original_title ) { #> no-title<# } #>">{{ data.title || data.original_title || wp.customize.Menus.data.l10n.untitled }}</span> <# if ( 0 === data.depth ) { #> <span class="is-submenu" style="display: none;"><?php _e( 'sub item' ); ?></span> <# } else { #> <span class="is-submenu"><?php _e( 'sub item' ); ?></span> <# } #> </span> <span class="item-controls"> <button type="button" class="button-link item-edit" aria-expanded="false"><span class="screen-reader-text"> <# if ( 0 === data.depth ) { #> <?php /* translators: 1: Title of a menu item, 2: Type of a menu item. 3: Item index, 4: Total items. */ printf( __( 'Edit %1$s (%2$s, %3$d of %4$d)' ), '{{ data.title || data.original_title || wp.customize.Menus.data.l10n.untitled }}', '{{ data.item_type_label }}', '', '' ); ?> <# } else if ( 1 === data.depth ) { #> <?php /* translators: 1: Title of a menu item, 2: Type of a menu item, 3, Item index, 4, Total items, 5: Item parent. */ printf( __( 'Edit %1$s (%2$s, sub-item %3$d of %4$d under %5$s)' ), '{{ data.title || data.original_title || wp.customize.Menus.data.l10n.untitled }}', '{{ data.item_type_label }}', '', '', '' ); ?> <# } else { #> <?php /* translators: 1: Title of a menu item, 2: Type of a menu item, 3, Item index, 4, Total items, 5: Item parent, 6: Item depth. */ printf( __( 'Edit %1$s (%2$s, sub-item %3$d of %4$d under %5$s, level %6$s)' ), '{{ data.title || data.original_title || wp.customize.Menus.data.l10n.untitled }}', '{{ data.item_type_label }}', '', '', '', '{{data.depth}}' ); ?> <# } #> </span><span class="toggle-indicator" aria-hidden="true"></span></button> <button type="button" class="button-link item-delete submitdelete deletion"><span class="screen-reader-text"> <?php /* translators: 1: Title of a menu item, 2: Type of a menu item. */ printf( __( 'Remove Menu Item: %1$s (%2$s)' ), '{{ data.title || data.original_title || wp.customize.Menus.data.l10n.untitled }}', '{{ data.item_type_label }}' ); ?> </span></button> </span> </div> </div> <div class="menu-item-settings" id="menu-item-settings-{{ data.menu_item_id }}"> <# if ( 'custom' === data.item_type ) { #> <p class="field-url description description-thin"> <label for="edit-menu-item-url-{{ data.menu_item_id }}"> <?php _e( 'URL' ); ?><br /> <input class="widefat code edit-menu-item-url" type="text" id="edit-menu-item-url-{{ data.menu_item_id }}" name="menu-item-url" /> </label> </p> <# } #> <p class="description description-thin"> <label for="edit-menu-item-title-{{ data.menu_item_id }}"> <?php _e( 'Navigation Label' ); ?><br /> <input type="text" id="edit-menu-item-title-{{ data.menu_item_id }}" placeholder="{{ data.original_title }}" class="widefat edit-menu-item-title" name="menu-item-title" /> </label> </p> <p class="field-link-target description description-thin"> <label for="edit-menu-item-target-{{ data.menu_item_id }}"> <input type="checkbox" id="edit-menu-item-target-{{ data.menu_item_id }}" class="edit-menu-item-target" value="_blank" name="menu-item-target" /> <?php _e( 'Open link in a new tab' ); ?> </label> </p> <p class="field-title-attribute field-attr-title description description-thin"> <label for="edit-menu-item-attr-title-{{ data.menu_item_id }}"> <?php _e( 'Title Attribute' ); ?><br /> <input type="text" id="edit-menu-item-attr-title-{{ data.menu_item_id }}" class="widefat edit-menu-item-attr-title" name="menu-item-attr-title" /> </label> </p> <p class="field-css-classes description description-thin"> <label for="edit-menu-item-classes-{{ data.menu_item_id }}"> <?php _e( 'CSS Classes' ); ?><br /> <input type="text" id="edit-menu-item-classes-{{ data.menu_item_id }}" class="widefat code edit-menu-item-classes" name="menu-item-classes" /> </label> </p> <p class="field-xfn description description-thin"> <label for="edit-menu-item-xfn-{{ data.menu_item_id }}"> <?php _e( 'Link Relationship (XFN)' ); ?><br /> <input type="text" id="edit-menu-item-xfn-{{ data.menu_item_id }}" class="widefat code edit-menu-item-xfn" name="menu-item-xfn" />Introduced in 4.3.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/customize/class-wp-customize-nav-menu-item-control.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.