DEP-14 branches explained visually

[Otto Kekäläinen <otto@debian.org>]

Hi,

While discussing git-buildpackage use, various DEP-14 branches,
pristine-tar purpose, how to correctly filter/repackage upstream
tarballs in past 6 months I noticed that many people have
misconceptions of what is the purpose of the various branches and how
git merges across them are supposed to work.

In addition to contributing to git-buildpackage man pages and other
documentation, I now also wrote this:
https://optimizedbyotto.com/post/debian-source-package-git/

I hope that in particular the diagrams it has will help anyone
interested in the topic to grasp quickly and easily how the git
branches work.

- Otto