WordPress at a glance
action is not described

network_admin_notices action-hook . WP 3.1.0

Prints network admin screen notices.

Usage

add_action( 'network_admin_notices', 'action_function_name_5147' );
function action_function_name_5147(){
	// action...
}

Where the hook is called

In file: /wp-admin/admin-header.php
network_admin_notices
wp-admin/admin-header.php 250
do_action( 'network_admin_notices' );

Where the hook is used (in WP core)

wp-admin/includes/ms-admin-filters.php 15
add_action( 'network_admin_notices', 'new_user_email_admin_notice' );
wp-admin/includes/ms-admin-filters.php 36
add_action( 'network_admin_notices', 'site_admin_notice' );
wp-admin/includes/ms-admin-filters.php 39
add_action( 'network_admin_notices', 'update_nag', 3 );
wp-admin/includes/ms-admin-filters.php 40
add_action( 'network_admin_notices', 'maintenance_nag', 10 );