WordPress at a glance
action is not described

load-widgets.php action-hook . WP 2.8.0

Fires early when editing the widgets displayed in sidebars.

Usage

add_action( 'load-widgets.php', 'action_function_name_5330' );
function action_function_name_5330(){
	// action...
}

Where the hook is called

wp_ajax_save_widget()
load-widgets.php
WP_Customize_Widgets::customize_controls_init()
load-widgets.php
WP_Customize_Widgets::wp_ajax_update_widget()
load-widgets.php
wp_ajax_delete_inactive_widgets()
load-widgets.php
wp-admin/includes/ajax-actions.php 2153
do_action( 'load-widgets.php' );
wp-includes/class-wp-customize-widgets.php 336
do_action( 'load-widgets.php' );
wp-includes/class-wp-customize-widgets.php 1539
do_action( 'load-widgets.php' );
wp-admin/includes/ajax-actions.php 2262
do_action( 'load-widgets.php' );

Where the hook is used (in WP core)

Does not used.