The big ones are definitely just the current user and the current device ID. Given what commands are available I can't think of anything else that would be useful. Maybe most recent GridMail ID so you could delete it from within a program, but that would require a new command be added.
The only others I could think to add would be Current program name, heat value, number of program uses remaining. Those don't seem like they'd have much functional use though outside of logging.