Local installation might break your server

[jaraco]

I'm interested in installing Algo to an Ubuntu server that I use to host other services (such as some web servers). I previously used PPTP to provide tunneling through the server and I'd like to replace that with a more secure VPN solution and Algo looks to be a good fit. When I follow the installation instructions, however, after choosing 12. Install to existing Ubuntu latest LTS server (for more advanced users), I come to a scary prompt:

https://trailofbits.github.io/algo/deploy-to-ubuntu.html

Local installation might break your server. Use at your own risk.

Proceed? Press ENTER to continue or CTRL+C and A to abort...:

It's unclear to me from those documents what's going to happen if I proceed. Following the link provided, the next link to AlgoVPN and Firewalls is broken, but I did manage to find the referenced content when traversing the docs through the source.

It's still unclear from that documentation what changes Algo will make to the system and what it would take to undo those changes should anything go wrong.

The docs also say some things that give me pause:

Make sure your target server is running an unmodified copy of the operating system version specified.

What if I have modified the system? What if I'm running from a user that I've created? Can I see what steps would be executed (and maybe work through those manually)?