Mike Shroepfer, Mozilla VP of Technology announced today a draft plan for Firefox and the Mozilla platform beyond the upcoming Firefox 3 (and attached Mozilla platform 1.9) release next June.

Most notable is Firefox 3.1, the next update to the Firefox 3 branch. It would add a few features that were not ready to ship in Firefox 3 development time frame. Among the most relevant:

Support for the <video> as defined in the HTML 5 specification. Chris Double has been working on this for about a year now and there are even a few experimental Firefox builds featuring it with native Theora (Ogg) support. Whether or not a certain codec must be part of the specification was the subject of a lengthy discussion last year. Sadly, one of the reasons to oppose Theora as a mandatory codec is the fear of a submarine patent that could make browser vendors vulnerable to a patent lawsuit.

Support for cross-site XMLHttpRequests (XHR) which would allow more powerful web applications and an easier way to implement mashup. Support for cross site XHR was pulled out of Firefox 3 code due to ate changes to the specification.

More power for Firefox 3’s location bar. Mike Beltzner, Firefox 3 lead, talked recently about how the search and location bars could be merged. In an intuitive way. SeaMonkey -and the Mozilla suite before- already does this but the implementation is not the most discoverable.

More performance tuning, better system integration.

Native JSON DOM binding, a powerful feature for web developers.

It would branch from the Mozilla2 code (known as mozilla-central, in the works for eight months already) sometime this summer, in Mercurial, the new version control system Mozilla is moving to from CVS.

Firefox 3.1 would be targeted for this year’s to intentionally coincide with Firefox Mobile (Fennec) development and release, making it the fastest update in Firefox history. It usually takes about a year between releases.

Firefox 4 is targeted for late 2009 (back to year long development cycles) and would introduce Mozilla2, an extensive update to the Mozilla platform to feature highlights like ActionMonkey, the merge of Mozilla’s JavaScript engine (SpiderMonkey) and Tamarin, Adobe’s JavaScript virtual machine open-sourced in late 2006.