Firefox 3.6 beta 1 introduced most of the new features, most visibly the ability to customize Firefox's look through Personas, less than two weeks ago. But among the 190 patches in the new beta is what Mike Beltzner, Mozilla's director of Firefox, described in a blog post as "a mechanism to prevent incompatible software from crashing Firefox."
There also are a number of deeper changes in Firefox 3.6 that Web developers likely will be more interested in. Note that one of them, the ability to use color gradients with formatting technology called Cascading Style Sheets (CSS), has changed syntax in between Firefox 3.6 beta 1 and beta 2.
Mozilla is trying to accelerate the pace of Firefox releases; Firefox 3.7 is set for release in the first half of 2010 and 4.0 some time later that year. The project faces new competition from Google's Chrome browser.