diff --git a/src/wp-includes/user.php b/src/wp-includes/user.php
index 1cd2db22e5..eae02db611 100644
--- a/src/wp-includes/user.php
+++ b/src/wp-includes/user.php
@@ -2351,13 +2351,16 @@ function wp_create_user($username, $password, $email = '') {
 }
 
 /**
- * Return a list of meta keys that wp_insert_user() is supposed to set.
+ * Returns a list of meta keys to be (maybe) populated in wp_update_user().
+ *
+ * Values actually keys returned via this function are dependent on the presence
+ * of those keys in the user meta data.
  *
  * @since 3.3.0
  * @access private
  *
  * @param WP_User $user WP_User instance.
- * @return array
+ * @return array List of user keys to be populated in wp_update_user().
  */
 function _get_additional_user_keys( $user ) {
 	$keys = array( 'first_name', 'last_name', 'nickname', 'description', 'rich_editing', 'comment_shortcuts', 'admin_color', 'use_ssl', 'show_admin_bar_front' );