2. Ok, it's not xterm. What is the VNC server/client? I don't see on in the code. When you use replit, what will cause it to trigger a magic VNC client? What if I want to try a different VNC server to speed it up? When will the VNC close...there's a lot of magic that I as a developer can't really work with and doesn't seem to be documented.

AFAICT, this demo is equivalent to, "someone ran VICE in a VNC". I think that's the OP's point.

It isn't even clear what VNC (or what its performance profile is).