WordPress at a glance
filter is not described

network_admin_url filter-hook . WP 3.0.0

Filters the network admin URL.

Usage

add_filter( 'network_admin_url', 'filter_function_name_2162', 10, 2 );
function filter_function_name_2162( $url, $path ){
	// filter...

	return $url;
}
$url(string)
The complete network admin URL including scheme and path.
$path(string)
Path relative to the network admin URL. Blank string if no path is specified.

Where the hook is called

network_admin_url()
wp-includes/link-template.php 3306
return apply_filters( 'network_admin_url', $url, $path );

Where the hook is used (in WP core)

Does not used.