WordPress at a glance
filter is not described

network_home_url filter-hook . WP 3.0.0

Filters the network home URL.

Usage

add_filter( 'network_home_url', 'filter_function_name_1607', 10, 3 );
function filter_function_name_1607( $url, $path, $orig_scheme ){
	// filter...

	return $url;
}
$url(string)
The complete network home URL including scheme and path.
$path(string)
Path relative to the network home URL. Blank string if no path is specified.
$orig_scheme(string/null)
Scheme to give the URL context. Accepts 'http', 'https', 'relative' or null.

Where the hook is called

network_home_url()
wp-includes/link-template.php 3275
return apply_filters( 'network_home_url', $url, $path, $orig_scheme);

Where the hook is used (in WP core)

Does not used.