Rated 4 out of 5 stars
This beloved extension may need a rewrite to keep working with Firefox 44 and beyond, even 42 and 43 fail to run it properly.
I've been grudgingly using HttpFox for now as an alternative but would be willing to give a small Amazon gift card to anyone who fixes live headers or a slightly larger one to anyone who rewrites and maintains it for future firefox.
Rated 3 out of 5 stars
Relied on this extension for years, now completely dead in FF42