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);
}