public function viewportsCommand($format = 'json', $packageKey = null)
    {
        $sitePackageKey = $packageKey ?: $this->getDefaultSitePackageKey();
        $viewportPresets = $this->configurationService->getSiteConfiguration($sitePackageKey, 'ui.viewportPresets');
        $this->outputData($viewportPresets, $format);
    }