Firefox Browser

Web Developer

"The Web Developer extension adds various web developer tools to a browser. The extension is available for Firefox and Chrome, and will run on any platform that these browsers support including Windows, Mac OS X and Linux.The Web Developer extension adds various web developer tools to a browser. The extension is available for Firefox and Chrome, and will run on any platform that these browsers support including Windows, Mac OS X and Linux.": Web Developer Extension; Also see:
Evaluating Web Sites for Accessibility with the Firefox Web Developer Toolbar

"FEBE (Firefox Environment Backup Extension) allows you to quickly and easily backup your Firefox extensions. In fact, it goes beyond just backing up -- It will actually rebuild your extensions individually into installable .xpi files. Now you can easily synchronize your office and home browsers.": FEBE @ Mozilla

FireFTP

"FireFTP is a free, secure, cross-platform FTP client for Mozilla Firefox which provides easy and intuitive access to FTP servers.": FireFTP @ Mozilla

NoScript

"Winner of the "2006 PC World World Class Award", this tool provides extra protection to your Firefox. It allows JavaScript, Java and other executable content to run only from trusted domains of your choice, e.g. your home-banking web site, and guards the "trust boundaries" against cross-site scripting attacks (XSS). Such a preemptive approach prevents exploitation of security vulnerabilities (known and even unknown!) with no loss of functionality... Experts do agree: Firefox is really safer with NoScript ;-)"
: NoScript Extension @ Mozilla

XMarks—Bookmarks backup and synchronization.

"If you use Firefox on more than one computer, you'll want XMarks. Install XMarks on each computer, and it will work silently in the background to keep your bookmarks synchronized. You can also log in to my.XMarks.com to manage your bookmarks from any computer.": XMarks Extension @ Mozilla

Configuration Mania

"There are various hidden preferences on firefox that are technical and difficult to configure with about:config. Configuration Mania allows you to do it easily. "You configure them in same way of firefox default option dialog, after opening this extension's setting dialog. Tool -> Options -> "Configuration Mania"... to open setting dialog. ": Configuration Mania Extension @ Mozilla

Greasemonkey

"Greasemonkey allows you to customize the way a webpage displays using small bits of JavaScript.: Greasemonkey

Universal Uploader

From Lifehacker: "The Firefox Universal Uploader extension (aka fireuploader) uploads and downloads files to and from popular web sites through a simple dual-pane interface. In essence, the Universal Uploader acts very much like previously mentioned FireFTP —the extension that turns Firefox into an FTP client—but it uploads directly to popular web sites like Flickr, Facebook, Google Docs, Picasa, Box.net, and YouTube. So rather than require you to log in to those sites to upload photos, videos, documents, or other files, you can fire up this extension and simply drag and drop files to the webapp you want to upload to. The extension is a little rough around the edges, but it's a great idea and works as advertised.": LifeHacker Article; Firefox Universal Uploader [Firefox Add-ons]

Extended Copy Menu (fix version)

"Provides the option to copy selection as plain text or html.

"It adds a "Copy As Html" and "Copy As Plain Text" to the context (right-click) menu. It is useful if you want to copy the text or underlying html from a web page into documents, posts or other applications."

Extended Copy Menu (fix version)