The latest iteration of the popular browser arrives just months after the official release of Firefox 4 in March 2011, which racked up an impressive 200 million downloads.
So, whats's new in Firefox 5?
Well, the browser offers more than 1,000 improvements and performance enhancements, along with support for more "modern" Web technologies.
For example, Firefox for Windows, Mac and Linux now support the CSS Animations standard - which is used by developers to build next-gen web apps and sites.
In addition, the new Firefox add-on SDK enables local development of add-ons, while the Builder Beta provides a convenient hosted Web-based build environment.
Developers can also code Firefox Add-ons for all platforms that install and update - without requiring a browser restart.
Finally, Mozilla has equipped FF for Android with a "Do Not Track" privacy feature, making Firefox the first browser to support such an option on multiple platforms.
As you may recall, Mozilla created Do Not Track to provide users with more control over the way their browsing behavior is tracked and used on the Web.
The feature, which lets users tell websites that they wish to opt-out of online behavioral tracking, is now easier to find in Firefox Preferences across all versions of the browser.