I'm more interested in the TLDR of how this works. Due to firewalls and such, it's technically impossible to have a peer to peer network without requiring port forwarding on at least one side. I wonder if they're really requiring that from users that want to use this.

Another way would be to do TCP or UDP hole punching, but that involves a third party for initial setup. Probably possible and probably safe, but I'd like to see a security review of that.