WordPress at a glance
action is not described

widgets_admin_page action-hook . WP 3.0.0

Fires before the Widgets administration page content loads.

Usage

add_action( 'widgets_admin_page', 'action_function_name_3870' );
function action_function_name_3870(){
	// action...
}

Where the hook is called

In file: /wp-admin/widgets.php
widgets_admin_page
wp-admin/widgets.php 424
do_action( 'widgets_admin_page' );

Where the hook is used (in WP core)

Does not used.