Google Page Speed - https://dl-ssl.google.com/page-speed/current/page-speed.xpi
The easy way to download and convert Web videos from hundreds of YouTube-like sites.
The Web Developer extension adds various web developer tools to the browser.
View HTTP headers of a page and while browsing.
Useful tools for the nightly tester.
Collections are groups of related add-ons that anyone can create and share.Explore Collections