That particular PR is from the working team that's drafting "API 2.0" and in this case is a checkpoint PR -- even if it were merged, it wouldn't be a full, working API yet. That PR is just like saying "hey, here's the bones of the thing we've got laid down already, are we on the right track?" The next step is that mark will review the bones for content, style, architecture, load, security, etc (and it is on his to-do list) and provide feedback, both of the "how this particular PR needs to be changed" and "hey, keep this in mind for when you add the next set of API calls" variety. Mark's day job has been unexpectedly busy lately, though, so he hasn't had the uninterrupted block of time necessary to do the code review!

(I totally know that the lack of a mobile app is the biggest problem most people have with DW right now! But we're putting as much of our attention to it as we can.)