How the game should detect, if it is a normal map or a jumpmap?
Not map, but server. You may check for 'JUMP' in server name. But really imo that's not necessary - not that it's really any kind of hidden information anyway.
While we're at it, if it wasn't mentioned, what would really be nice for server browser, besides password column, is querying for information about GLS setting on the server, ie. whether you need to be logged in to play.