Reverse engineering the EQSO protocol

EQSO is an Amateur radio software that connect PMR radios over the internet using internet gateways.

When I was a child, before I ever had my own radio, I used to hang out in EQSO servers, listen to other people and talk to them in order to learn about radio. At some point I noticed that EQSO was still a thing, and although the activity was almost dead, it was still possible to get a server list and connect to some servers.