protected function getCompatibilityComment()
    {
        $compatibilityComment = null;

        foreach ($this->getCommentSections() as $commentSection) {
            // Compatible in IE6+, Firefox 2+, Safari 4+.
            // Compatibility: IE6+, Firefox 2+, Safari 4+.
            // Compatibility untested.
            if (preg_match('/^\s*Compatib(le|ility):?\s+/i', $commentSection)) {
                $compatibilityComment = $commentSection;
                break;
            }
        }

        return $compatibilityComment;
    }