A selection from QA kung foo master Ms. Paula Herculano, here it comes:
https://addons.mozilla.org/pt-BR/firefox/collection/qahelper
One more thing I wanted to add on Paula’s list: LiveHTTPHeaders a very powerful tool to display HTTP headers in real time.
(ok, ok…we can use firebug from the original list to do some HTTP header scan, but LiveHTTPHeaders definitely has a better support for this dirty job).
