Index: src/wp-admin/widgets.php
===================================================================
--- src/wp-admin/widgets.php	(revision 25721)
+++ src/wp-admin/widgets.php	(working copy)
@@ -34,6 +34,15 @@
 		wp_enqueue_script( 'jquery-touch-punch' );
 }
 
+/**
+ * Fires early when editing the widgets displayed in sidebars.
+ *
+ * Triggered after widgets are set up ($wp_registered_widgets and
+ * $wp_registered_widget_controls are defined), but before other
+ * actions on the widgets are taken.
+ *
+ * @since 2.2.0
+ */
 do_action( 'sidebar_admin_setup' );
 
 $title = __( 'Widgets' );
@@ -315,7 +324,15 @@
 <div id="message" class="error"><p><?php echo $errors[$_GET['error']]; ?></p></div>
 <?php } ?>
 
-<?php do_action( 'widgets_admin_page' ); ?>
+<?php 
+/**
+ * Fires after the title, but before available widgets and sidebars have loaded.
+ *
+ * Displays content on the widget admin page before the main page content.
+ *
+ * @since 3.0.0
+ */
+do_action( 'widgets_admin_page' ); ?>
 
 <div class="widget-liquid-left">
 <div id="widgets-left">
@@ -396,5 +413,13 @@
 </div>
 
 <?php
+
+/**
+ * Fires after the available widgets and sidebars have loaded.
+ *
+ * Displays content on the widget admin page as part of the main page content.
+ *
+ * @since 2.2.0
+ */
 do_action( 'sidebar_admin_page' );
 require_once( ABSPATH . 'wp-admin/admin-footer.php' );