diff --git a/src/wp-includes/option.php b/src/wp-includes/option.php
index a6f20913d0..72f6999184 100644
--- a/src/wp-includes/option.php
+++ b/src/wp-includes/option.php
@@ -941,11 +941,13 @@ function get_all_user_settings() {
  * Private. Set all user interface settings.
  *
  * @since 2.8.0
+ * @access private
  *
  * @global array $_updated_user_settings
  *
- * @param array $user_settings
- * @return bool|void
+ * @param array $user_settings User settings.
+ * @return bool|null False if the current user can't be found, null if the current
+ *                   user is not a super admin or a member of the site, otherwise true.
  */
 function wp_set_all_user_settings( $user_settings ) {
 	global $_updated_user_settings;