WordPress at a glance
action is not described

_network_admin_menu action-hook . WP 3.1.0

Fires before the administration menu loads in the Network Admin.

The hook fires before menus and sub-menus are removed based on user privileges.

Usage

add_action( '_network_admin_menu', 'action_function_name_9197' );
function action_function_name_9197(){
	// action...
}

Where the hook is called

In file: /wp-admin/includes/menu.php
_network_admin_menu
wp-admin/includes/menu.php 19
do_action( '_network_admin_menu' );

Where the hook is used (in WP core)

Does not used.