If this integer is non-zero, it is a session ID and the user is redirected to the account maintenance screen with the session ID tagged on to the URL.

It would allow for easier maintenance, if you were testing a constantly changing application, to create a separate XML document for each screen, or some other logical separation.

The assumed use case is to have custom text maintained by the IT Department to show in the Login screen to inform the user about maintenance downtimes or other important information.