public static function getFilenames(Config $config, $part)
{
$extensions = implode('|', array_map('preg_quote', $config['valid_content_extensions'])) . '|html';
$raw = preg_replace('/(.*)?\\.(' . $extensions . ')$/', '$1', $part);
$raw = Builder::removeSortingInformations($raw);
return ["{$raw}.html", $raw];
}