Patching Pacman

I'd like to try and patch pacman, to add a feature I need.

I cloned the git repository as described on the Pacman Home Page, but I noticed that there are two main branches:

• master, which I believe is used for development
• release/5.0.x, used for releases

The two branches seem to differ quite a lot. There are features pushed to master years ago that still haven't apperead in the release branch...

What's the workflow used for the development of pacman? Is it safe to run pacman built from master? Where should I add my changes?