The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.
The Web Developer extension adds various web developer tools to the browser.
FireFTP is a free, secure, cross-platform FTP/SFTP client for Mozilla Firefox which provides easy and intuitive access to FTP/SFTP servers.
Check out my new project, FireSSH!
Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.
YSlow analyzes web pages and suggests ways to improve their performance based on a set of rules for high performance web pages.
http://yslow.org is the official open source website.
Color tools for web development.
Color picker and eyedropper + saving colors and trying out colors with drag and drop.
FirePHP enables you to log to your Firebug Console using a simple PHP method call.
Not using Firebug 1.9+ on Firefox 8+? See http://firephp.org/
Finds HTML elements matching chosen CSS selector(s) or XPath expression
Firebug extension to view which CSS rules are actually used.
Pixel Perfect is a Firefox/Firebug extension that allows web developers and designers to easily overlay a web composition over top of the developed HTML.
Collections are groups of related add-ons that anyone can create and share.Explore Collections