Firefox is the only open source Web browser among the most used browsers on the Web as of March 2013. The open source nature of Firefox enables developers from all over the world to contribute code to the browser and extend the functionality of Firefox with add-ons and themes. | Firefox is the only open source Web browser among the most used browsers on the Web as of March 2013. The open source nature of Firefox enables developers from all over the world to contribute code to the browser and extend the functionality of Firefox with add-ons and themes. |