{guest} renders its content when nobody is logged in to this application, and the part after its own {else} - or the @else@ half - when someone is. It is {auth} turned round, without the user's row: the fields of the user are {auth}'s to give.

Like {auth} it never starts a session to find out: a visitor without a session cookie is a guest at once. The pair must close - a lone {guest} is an error under the strict check.