Author here. I've made the demo system public [1] but it's written just for me so it should be painful to set up the same environment.

The mechanism is pretty simple: a Node.js server (running on genuine Linux) listens on tcp:22. Once you connect, it boots a dedicated Firecracker microVM instance and forwards network packets between your SSH client and VM.

Regarding the command history, others (including I) can't see what you type. If you could, it must be a vulnerability.

[1] https://github.com/nuta/kerla-demo