public function guessRootFileFromUnzipped($hash)
    {
        // Grab all HTML files from Archive
        $htmlFiles = $this->getHTMLFiles($hash);

        // Only one file
        if (1 === count($htmlFiles)) {
            return array_shift($htmlFiles);
        }

        // Check usual default root files
        foreach ($this->defaultIndexFiles as $file) {
            if (in_array($file, $htmlFiles)) {
                return $file;
            }
        }

        // Unable to find an unique HTML file
        return;
    }