My old #GNUArch archives are now up on http://tla.madhouse-project.org/, and they can be registered and retrieved and all that.
It's not easy, though, and I will likely put up a README at the top level to explain how to make it work.
First: the TLA version in nixpkgs does not seem to play well with https, so the archives have to be registered with a http URL.
Second, tla get wants to use tar -m --preserve -zxf -, but modern tar considers --preserve ambigous, so I made a small wrapper that rewrites --preserve to --preserve-permissions. Then I could tla get my old stuff.
I originally wanted to resurrect some historic stuff from there, convert them to git, but... that's too much work for very little reward. I might do that some other time, but not today.