I've also spent some time to find this information. I couldn't find information about another install steps at the Internet (found it soon in README.Debian). I added the bug to hg-git project page, but it was closed, because the error denotes as Debian/Ubuntu package side error.
https://github.com/schacon/hg-git/issues/204 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/666292 Title: Path to hggit extension not automatically added, and not obvious -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
