Earlier quoted context omitted.
Mercurial queues. I thought that's what you meant with "patches".
Ah yes. MQ was the plugin used to create those patches, now I remember. They stopped using? Even on the main Firefox repo?
I actually rather like email-based code review. It's really easy to keep editing and rebasing your patch while people comment on it. If Mercurial Evolve picks up, this will be an awesome new way to work, especially if Kallithea or Bitbucket grows the features to support it.
However, current Mozilla development, AIUI, is moving towards ReviewBoard, although I have heard a growing mutinous group in Mozilla who just wants to chuck all homegrown solutions and slap all of their code on github like everyone else.