Oh that's fun. There's one git repo. There's another one on git.kernel.org, which normally I would prefer only we're eight months post-compromise and it's still empty. And if you go to the first website advertised in that mail post, its download page links to a subversion repository!
At this point I'd have to start digging into the last-modified date of each repo to see which was current and what their relationship was to the existing powertop 1.x repos... and life is just too short.