Index: src/wp-includes/class-wp-widget.php
===================================================================
--- src/wp-includes/class-wp-widget.php	(revision 37322)
+++ src/wp-includes/class-wp-widget.php	(working copy)
@@ -10,8 +10,8 @@
 /**
  * Core base class extended to register widgets.
  *
- * This class must be extended for each widget and WP_Widget::widget(), WP_Widget::update()
- * and WP_Widget::form() need to be overridden.
+ * This class must be extended for each widget, and WP_Widget::widget() must be overriden. WP_Widget::update()
+ * and WP_Widget::form() need to be overridden to add options to the widget.
  *
  * @since 2.8.0
  * @since 4.4.0 Moved to its own file from wp-includes/widgets.php