Mozilla representatives call version 3.5 a "preview" release, stressing that it's not a full release but more of a sneak-peek for technophiles who can't wait to try out the latest toys.
The open-source giant is inviting enterprising users to take it out for a test ride and tell them about any bugs they might find.
So what's new? Leading tech blog TechCrunch.com got a look at the new browser in action.
Most important, Firefox 3.5 constitutes a major competitor for the industry-leading Flash video format. Anyone who's played a YouTube video is familiar with the Flash format, but the new version of Firefox comes packaged with support for the open-source video formats Ogg Vorbis and Theora. The video-sharing site DailyMotion.com in these new formats.
"If this takes off, Flash video could be come history," TechCrunch's Erick Schonfeld said, adding that these open-source video solutions offer filmmakers and developers new and improved support for interactive elements that they can add directly into videos. Schonfeld said that Flash can support some of these bells and whistles, but that it's much easier to include such interactive content into open-source video formats.
"Being able to treat the content inside videos like web pages opens up a whole new world of possibilities for web video," he said.
In addition, users can tell Firefox their physical location, and Google will keep track of it, all without installing any extra browser plugins.
Of less interest to the adult industry is Firefox's new support for font, specifically downloaded ones.