Now, it's not your legal responsibility as the originator or current curator of the repo to help this person out, of course, but in terms of the industry and our behavior as software engineers it seems we do owe some sense of permanence to things that feel more like infrastructure than simple personal websites. I’ve been very guilty myself of stepping “briefly” away from things knowing in the back of my mind I may never return. I continue to try to reform my attitudes online. Remember BerliOS, Google Code, and CodePlex? Gna! is merely one of several, not even the most used.
Realizing this might appear an attack against the Gna! project owners, I had to reach out and talk about this with them and identify this as merely a conversation starter. The loss of Gna! definitely has made me think more about the ecosystem we work within and whether we are doing everything the way we should be doing. How many users of GitHub might be working under frightening conditions to get code out to the world they could be arrested for writing? We don't know. I merely propose we might have a gap here in the process that does not acknowledge users who may rely greatly on some of our tools we offer for "free" and that when we retire them, something important could be lost in the process.
Note: Sylvain Beucler, formerly of the Gna! project and notably of many great projects like Savane and FusionForge, reminded me ArchiveTeam volunteers are often working behind the scenes to keep snapshots of retires sites such as Gna! when able. That project is currently headed by one of my favorite ASCII-oriented minds, Jason Scott of textfiles.com. They are linked to below.