Mozilla Firefox 4 Beta 1 is available for testing purposes and the installation package is incomplete so some features might be either missing or not working properly.
One major change is the Tabs interface which is now located at the top of the browser and has been completely redesigned as seen in the screenshot below.
New Tab Location
New Firefox User Interface:
New Firefox UI
Some other new features:
- Add-Ons Manager
- Support for new CSS3 features
- Web Console: Webpage analysis tool
- HTML5 Support
- JetPack SDK (Making Add-On Development Easier)
Article Source: Mozilla.com
