It looks like they run an SSH server inside a Docker container defined by this Dockerfile [1]. This uses the ForceCommand directive in the sshd_config file to ensure that a specific command is run when a user connects (rather than the user connecting directly to a shell).

Depending on whether the user connects as the `playground` or `tutorial1` user they interact with a bash script that is either [2] or [3]; these run lnav, using the timeout command to limit how long users are connected for, and to kill the lnav process if it gets stuck.

[1]: https://github.com/tstack/lnav/blob/master/demo/Dockerfile

[2]: https://github.com/tstack/lnav/blob/master/docs/tutorials/pl...

[3]: https://github.com/tstack/lnav/blob/master/docs/tutorials/tu...