Firefox 3.1 Beta 3 is finally available for download. The development milestone represents a crucial point in the development of codename Shiretoko, as it is the last breath of Firefox 3.1. Mozilla has already announced the rebranding of Shiretoko from Firefox 3.1 to Firefox 3.5 as the open source browser evolves from Beta 3 to Beta 4 in the development process. Users will need to enjoy Firefox 3.1 Beta 3 as much as they can, since it's the last they'll ever see of Firefox 3.1. Ahead of the Beta 4 milestone, Mozilla will completely kill off 3.1, without having actually released the final version of this browser iteration.

“This milestone is focused on testing the core functionality provided by many new features and changes to the platform scheduled for Firefox 3.1,” revealed Mike Beltzner, Mozilla User Experience lead. “Firefox 3.1 Beta 3 is a public preview release intended for developer testing and community feedback. It includes many new features as well as improvements to performance, web compatibility, and speed.”

The new Beta release of Firefox 3.1 essentially paves the way for Firefox 3.5. However, Mozilla will not restart the Beta process from scratch, or from version 1. Instead, the Beta versions will continue to evolve as if they had done naturally. In this context, the upcoming development milestone of the open source browser will be Firefox 3.5 Beta 4. Mozilla estimated that Beta 4 of Firefox 3.5 would be delivered in April 2009.

“New features and changes in this milestone that require feedback include: improved the new Private Browsing Mode, including the ability to “Forget This Site” from the History sidebar. Improved performance and stability with the new TraceMonkey JavaScript engine. Improvements to web worker thread support. New native JSON support. Improvements to the Gecko layout engine, including speculative parsing for faster content rendering. Support for new web technologies such as the <video> and <audio> elements, the W3C Geolocation API, JavaScript query selectors, CSS 2.1 and 3 properties, SVG transforms and offline applications,” Beltzner added.


Firefox 3.1 Beta 3 for Windows is available here.

Firefox 3.1 Beta 3 for Linux is available here.

Firefox 3.1 Beta 3 for Mac OS X is available here.