Rated 5 out of 5 stars

A definite most essential addon. Its been very abandoned. I've tried to contact author and even offer a donation. ;(

In the mean time or in light of someone to take this over here is a way to make it work. While its meant for authors/developers it makes most of our old addons work. ;~)

Nightly Tester Tools
https://addons.mozilla.org/en-US/firefox/addon/6543

This review is for a previous version of the add-on (0.4.0.5.20070419).