Because the upstream BornAgain tarballs differ quite significantly from the upstream git repository (most notably, the pdf manual is missing from the tarballs) but it is still pretty useful to have the full upstream git history available, the branch layout is like this:
* debian: the debian packaging
* upstream: the upstream tarball releases (imported with pristine-tar), merged into debian after a new upstream release
* upstream-git/master: the upstream git master branch, never merged into the upstream or debian branches. Instead, cherry-picking from upstream-git/master to debian is done if needed.
