public static function show_after_install($markasviewed = null) {
        global $CFG;
        if (self::is_registered()) {
            $showregistration = false;
            $markasviewed = true;
        } else {
            $showregistration = !empty($CFG->registrationpending);
            if ($showregistration && !site_is_public()) {
                // If it's not a public site, don't redirect to registration, it won't work anyway.
                $showregistration = false;
                $markasviewed = true;
            }
        }
        if ($markasviewed !== null) {
            set_config('registrationpending', !$markasviewed);
        }
        return $showregistration;
    }