Mozilla tends to announce projects when they begin so people can contribute to them right away. I think that's a good thing and that's one of the reasons I work for Mozilla.

By the way, I think this is an awesome effort by Josh and the others working on this. I work mainly in security and networking, and I'm excited about anything we can do to make end-to-end communication more efficient because these kinds of improvements help enable more use of HTTPS and help reduce (hopefully eliminate) the need for content transforming proxies.

We would like to develop in the open, and hopefully with community participation.