diff --git a/src/wp-includes/widgets.php b/src/wp-includes/widgets.php
index d670afc4db..fab278c920 100644
--- a/src/wp-includes/widgets.php
+++ b/src/wp-includes/widgets.php
@@ -513,13 +513,18 @@ function wp_register_widget_control( $id, $name, $control_callback, $options = a
 }
 
 /**
+ * Registers the update callback for a widget.
+ *
+ * @since 2.8.0
+ *
  * @global array $wp_registered_widget_updates
  *
- * @param string   $id_base
- * @param callable $update_callback
- * @param array    $options
+ * @param string   $id_base         The base ID of a widget created by extending WP_Widget.
+ * @param callable $update_callback Update callback method for the widget.
+ * @param array    $options         Optional. Widget control options. See {@see wp_register_widget_control()}.
+ *                                  Default empty array.
  */
-function _register_widget_update_callback($id_base, $update_callback, $options = array()) {
+function _register_widget_update_callback( $id_base, $update_callback, $options = array() ) {
 	global $wp_registered_widget_updates;
 
 	if ( isset($wp_registered_widget_updates[$id_base]) ) {