This release, which requires at least 8.5.3 CD5 beta, features the same bug fixes/additions than the corresponding 8.5.2 build, including Firebug Lite.
But wait, the biggest news is coming. I'm proud to announce that this release includes support for relational data access. Yes, read it again: it includes RDBMS support :-)
It features some new data sources, design elements, @functions... all designed to make relational data access easy. See Niklas' video, as well as the included deck of slides, to get a sense of what it enables.
Of course, we'll appreciate your feedback on this new feature and how we can make it better. I expect activity on the forums!