It's not like the postfix code is hidden, or even difficult to find. Nothing is being done in secret here. If you want to work on a new feature that'll take a

It's not like the postfix code is hidden, or even difficult to find. Nothing is being done in secret here. If you want to work on a new feature that'll take a long time and require several people, grab the code, stick it in git, and work on it with your team. Once the work is done, send a patch to the postfix maintainer, and he'll merge it if it's worthwhile. Linus created git because the above workflow was killing him trying to handle the patches for the Linux kernel. He was doing it almost exactly as described above for a long time. I suspect postfix sees a far lower volume, and the above workflow probably works just fine.