public static function fromArrayAndSettings($cfg, $settings, $artifact = null) {
        $chunkSpecification = new static($cfg, $settings->getDirectory());
        $chunkSpecification->set("source", null);
        $chunkSpecification->set("target", fphp\Helper\Path::join(
            $settings->getOptional("target", null), $chunkSpecification->getTarget()));
        return $chunkSpecification;
    }