Firefox (formerly known as Phoenix and Firebird) is a cross-platform, powerful, usable, and standards-compliant Web browser, based on the Mozilla framework. It is written using the XUL user interface language and was designed to be cross-platform.
The Gecko rendering platform was upgraded to version 1.9.2. New features include lightweight themes called Personas, protection from out-of-date plugins, fullscreen native video, better performance, and better standards support.