Rated 3 out of 5 stars

Seems like you don't realize it, but you can already debug Firefox using the built-in developer tools:
1. Open the built-in devtools.
2. Click the settings icon and check "Enable chrome and add-on debugging" and "Enable remote debugging."
3. Restart Firefox.

You will now have new options in the Web Developer Tools menu:
- Browser Toolbox: Used to inspect and debug the browser
- Browser Console: console.log, console.dir etc. log to this

This review is for a previous version of the add-on (