Release Notes 3.1-m3 ("Milestone 3")
Milestones 2 and 3 don't have many feature-changes, because a lot of the development happens on branches and under the hood. We have been doing some UI polish, but nothing large is to be seen yet.
We did however split up resource-loading, so CSS is now at the top of the page, and JS is at the bottom, resulting in faster page views. If you are a plugin author using resource bundles and JS/CSS (which you should, obviouslu), then definitely check out this milestone to see if your plugin works as expected.
Stay tuned for M4 in about two weeks, which will show off some nice new feature improvements.
Per and the Confluence development team