private function getDefaultOutputAs()
    {
        $ret = 'html';
        $interface = $this->debug->utilities->getInterface();
        if ($interface == 'ajax') {
            $ret = $this->cfg['outputAsDefaultNonHtml'];
        } elseif ($interface == 'http') {
            $contentType = $this->debug->utilities->getResponseHeader();
            if ($contentType && $contentType !== 'text/html') {
                $ret = $this->cfg['outputAsDefaultNonHtml'];
            }
        } else {
            $ret = 'text';
        }
        return $ret;
    }