in src/main/java/org/apache/sling/auth/xing/login/impl/XingLoginAuthenticationHandler.java [225:233]
    public void dropCredentials(final HttpServletRequest request, final HttpServletResponse response) throws IOException {
        logger.debug("drop credentials");
        // delete cookies
        deleteCookies(request, response);
        // redirect and call JavaScript xing.logout()
        final HashMap<String, String> params = new HashMap<String, String>();
        logger.debug("redirecting to '{}'", logoutPath);
        AuthUtil.sendRedirect(request, response, logoutPath, params);
    }