I therefore created a brand new version of the repo. In the new one, I'm structuring things a bit differently. Rather than trying to keep one branch going, I'm going to have multiple named branches.
The first one is default, or the comm-central import. The tip of the default branch is the tip of comm-central when I imported that.
One set of branches is the experimental let's-add-new-address-book-type branches. I already have a prototype SQL AB developement branch, sqlab. When I start experimenting with Evolution support, there will be an evolutionab branch. And so forth and so on. If you have custom AB types that you want to publish, email me a bundle and you'll get your very own named branch in this repo (for as long as it exists).
Another set of branches is the bugs I'll be working on. These branches will tangle around each other as a fix one bug or another, since some bugs depend on other bugs. I'll try to keep a last-idl tag up-to-date such that any changes on a branch after the last branch point or this tag (which ever comes later) do not change any IDL files.