Besides a security update, Mozilla the fourth beta of Firefox 3.5 (previously 3.1), which will be the next major release this year for the most ferocious rebel browser in the world.

The fourth and final beta, before we see release candidates, sports a new feature, which allows you to restore Firefox windows next to restoring tabs. Other changes include polishing of the user interface for private browsing mode, which now integrates nicely with the settings for history.

If you've forgotten, or haven't followed the latest and greatest Firefox betas, 3.5 comes with: a faster JavaScript engine named TraceMonkey (similar in performance to Chrome's V8 and Safari's Nitro), private browsing mode (for anonymous browsing, without interfering with cache/history), geolocation, native JSON, web worker threads, faster page rendering, increased standards support (including web fonts), and much much more.

Of course it remains a beta, but Firefox 3.5 looks to become a solid evolution and eager users and web developers are invited to test this release.