protected function getQualityHeader($serverIndex, $name)
    {
        $httpServer = $this->getHeaderLine($serverIndex);
        $parts = preg_split('/,\\s*/', $httpServer);

        $output = [];
        foreach ($parts as $part) {
            $headerParts = explode(';', $part);
            if (isset($headerParts[1])) {
                $qualityPart = $headerParts[1];
                $qVal = substr($qualityPart, 2);
                $quality = ($qVal == (int)$qVal) ? (int)$qVal : (float)$qVal;
            } else {
                $quality = 1;
            }

            $headerName = $headerParts[0];
            $output[] = [$name => $headerName, 'quality' => $quality];
        }

        return $output;
    }