The real mystery is what it's running on. Multics originally ran
on the GE/H 600(0) systems. I doubt any are still around. It's
probably a simulator but I've never heard of one for the H6000.

A simulator. Originally running Multics release 12.5, but a dedicated team of new and original Multicians have completed the Y2K transition, fixed some bugs and added some features, so now running release 12.6f.

All of the original systems are believed to be destroyed with the exception of DOCKMASTER (an NSA machine), now in possession of the National Cryptographic Museum, but warehoused.

A video of the Living Computer Museum's Multics emulator (with maintenance panel) booting: https://www.youtube.com/watch?v=jni7wk7bjxA

At least one of the new Multicians (me) is subscribed to TUHS.

-- Charles