Controller/ContactController.php
private function getContactFormMethod()
    {
        $method = self::CONTACT_FORM_METHOD_DEFAULT;

        if ($configMethod = \OxidEsales\Eshop\Core\Registry::getConfig()->getConfigParam('OeGdprOptinContactFormMethod')) {
            $method = $configMethod;
        }

        return $method;
    }
private function getContactFormMethod()
    {
        $method = self::CONTACT_FORM_METHOD_DEFAULT;

        if ($configMethod = \OxidEsales\Eshop\Core\Registry::getConfig()->getConfigParam('OeGdprOptinContactFormMethod')) {
            $method = $configMethod;
        }

        return $method;
    }
Get currently selected contact form opt in method

@return string