diff --git a/src/wp-admin/includes/menu.php b/src/wp-admin/includes/menu.php
index 6cb474b38d..27dd91540b 100644
--- a/src/wp-admin/includes/menu.php
+++ b/src/wp-admin/includes/menu.php
@@ -187,9 +187,13 @@ foreach ( $menu as $id => $data ) {
 unset( $id, $data, $subs, $first_sub );
 
 /**
- * @param string $class_to_add
- * @param string $classes
- * @return string
+ * Adds a CSS class to a string.
+ *
+ * @since 2.7.0
+ *
+ * @param string $class_to_add The CSS class to add.
+ * @param string $classes      The string to add the CSS class to.
+ * @return string The string with the CSS class added.
  */
 function add_cssclass( $class_to_add, $classes ) {
 	if ( empty( $classes ) ) {
@@ -200,8 +204,14 @@ function add_cssclass( $class_to_add, $classes ) {
 }
 
 /**
- * @param array $menu
- * @return array
+ * Adds CSS classes for top-level administration menu items.
+ *
+ * The list of added classes includes `.menu-top-first` and `.menu-top-last`.
+ *
+ * @since 2.7.0
+ *
+ * @param array $menu The array of administration menu items.
+ * @return array The array of administration menu items with the CSS classes added.
  */
 function add_menu_classes( $menu ) {
 	$first     = false;
@@ -239,7 +249,7 @@ function add_menu_classes( $menu ) {
 	}
 
 	/**
-	 * Filters administration menus array with classes added for top-level items.
+	 * Filters administration menu array with classes added for top-level items.
 	 *
 	 * @since 2.7.0
 	 *
@@ -354,4 +364,3 @@ if ( ! user_can_access_admin_page() ) {
 }
 
 $menu = add_menu_classes( $menu );
-                		
\ No newline at end of file