It's rather unclear how this integrates with the OS you run on top of.

I think a short explanation of how this actually works (not the post-quantum crypto part, but rather the plumbing into the networking stack of your box) would be very helpful.

[EDIT]: an a very quick first glance at the python source code and the install scripts reveals that a PQconnect install performs rather intrusive changes to your system:

    - installs lots of packages
    - installs a daemon running under systemd
    - creates a new user
    - creates a new tunnel network device

I'm going to take a wild initial guess and assume that there's some dynamic manipulation of low-level networking state (routing tables, iptables, etc...), which makes me rather queasy to install this on a production and/or work system because I have no idea if it is going to wreck my existing setup.

Also, the server is written in python ... I most certainly hope the python code is not in any way processing / redirecting network traffic itself in userland, or performance is going to be awful.

All of this points to the fact that an overview of how pqconnect grafts itself into your Linux system would be most welcome.