Filter sites from NS cloner

ns-cloner-filter-sites.php

<?php

/**
 * Filter out sites to show in cloning list.
 */
add_filter( 'ns_cloner_sites_list', function( $sites ) {
	$my_site_ids = array( 1, 10, 3, 8, 13 ); // The site ids you only want to show. Replace with the ids of your sites.
	foreach ( $sites as $id => $name ) {
		if ( ! in_array( $id, $my_site_ids, true ) ) {
			unset( $sites[ $id ] );
		}
	}
	return $sites;
});