What needs still to be done for Firefox 3.1 beta 2

Now the developer release of Firefox 3.1 beta 1 is almost hitting the road, it's time to look what's coming next. Together with the release of beta 1 code freeze is active now. New features may not land in beta 2, because they can bring new bugs and instability. Still some important new features hasn't landed yet. Of most features the backend is already ready, but there is stil need for UI changes or minor code changes. Therefor there is made a list of features that may land in beta 2. Some highlighted in this post.
First of the features that will get finalysed is the <video> tag. The backend is as good as done. Now it is time to get neutral default controls cross platform and they need to be themeable aswell. Beta 2 should also contain the possibility to seek/scrub.
Another feature that still needs to get some UI design is the private browsing mode. The backend is also as good as done, UI design still didn't started yet.
A lot of changes in the field of plugins is also allowed to get a little bit later. There is already a way to 'prevent users from running out of date plugins that represent security risks ' and 'prohibit users from using plugins known to be vulnerable ', but there should come a nice warning on startup of the browser. Also the developers want to bring back the expierence of plugins discovered and installed for the user like in Firefox 2.0 back.
So there is still alot of work before the release of Firefox 3.1, but it will be an enormous improvement and completion of Firefox 3.0.