Mantra is a collection of hacking tools, add-ons, and scripts based on Firefox.
Some of the features of Mantra
1. Its built on top of the browser – Saves lots of man power and learning curve.
2. It is Cross platform and flexible – It can easily run on Windows, Mac and Linux natively
3. Its free as “free beer” and “free speech”
4. Its open source, so you are free to use it or modify it your own way.