WordPress at a glance
action is not described

add_admin_bar_menus action-hook . WP 3.1.0

Fires after menus are added to the menu bar.

Usage

add_action( 'add_admin_bar_menus', 'action_function_name_1628' );
function action_function_name_1628(){
	// action...
}

Where the hook is called

WP_Admin_Bar::add_menus()
wp-includes/class-wp-admin-bar.php 601
do_action( 'add_admin_bar_menus' );

Where the hook is used (in WP core)

Does not used.