Mozilla has released the third beta of Firefox 3.1, patiently polishing the biggest competitor to the world's most used browser.

The changes is this beta aren't huge compared with the previous one as all focus is on stabilizing the release, of which most importantly is the faster JavaScript engine TraceMonkey. Compared with Firefox 3.0 this release includes: private browsing mode, web worker thread support, native JSON support, improvements to the Gecko layout engine (including speculative parsing for faster content rendering), support for new web technologies.

For those who haven't toyed with Firefox 3.1 yet, be sure to note that it might break some add-ons. You can download Firefox 3.1 Beta 3 here, but don't forget to read the release notes before using this release. If you're wondering why this release isn't called Firefox 3.5 yet, that's because it will be re-branded starting from beta 4 (the last beta).