WordPress at a glance
filter is not described

the_networks filter-hook . WP 4.6.0

Filters the network query results.

Usage

add_filter( 'the_networks', 'filter_function_name_8325', 10, 2 );
function filter_function_name_8325( $_networks, $this ){
	// filter...

	return $_networks;
}
$_networks(array)
An array of WP_Network objects.
$this(WP_Network_Query)
Current instance of WP_Network_Query (passed by reference).

Where the hook is called

WP_Network_Query::get_networks()
wp-includes/class-wp-network-query.php 266
$_networks = apply_filters_ref_array( 'the_networks', array( $_networks, &$this ) );

Where the hook is used (in WP core)

Does not used.