Just finished the Mercurial 2.3 developer sprint on behalf of the company I work for, Edlund A/S. It was really nice to meet a lot of the familiar faces and the new ones from Facebook and Wolfram Research. It is especially in meetups like these that you truly get to experience the friendliness that's part of the people around the Mercurial project. Some of my more noteworthy contributions around the Mercurial eco-system during the sprint were: Release RepoMan, the repository forest manager that we have developed at Edlund A/S for managing a complex multi-repository setup where some modules are individually co-dependent but we want to be able to modify all of them coherently at the same time.
As one of the primary developers touching certificates in the Mercurial world, I am often asked how they work, what people need to do to use them and how they can work well with Mercurial. A principal thing to remember here is that Mercurial will not work as a complete server out of the box, requesting authentication information, in the form of basic, digest, or certificates, at all. This means that in order to use X.509 certificates with Mercurial, one needs to place a web server that knows of these authentication mechanisms in front of it.