[rekado]

You can still use a bug tracker with an email-based workflow. Many GNU projects use debbugs.gnu.org, which helps to keep track of patches that have been sent to the mailing list.

I can see how it would be inconvenient for people who use an inflexible email client or editor, though. (I'm trying to make this workflow a little less intimidating for Guix by working on a more convenient web interface on top of debbugs.)