Gopher itself is spec’d out in RFC-1436. It’s not a particularly difficult protocol to implement. It’s easier than HTTP/1.1 (though not necessarily pre-1.0 versions; those are basic in an under-designed way, and I’d say the same about Gopher). I don’t know if that licensing fee claim holds up. People may have been worried about it at the time, but UMN never had a patent on it or anything, and RFC’s are public. If there were fees charged, it’d be the creators themselves charging them.