FirePath Requires Restart
FirePath is a Firebug extension that adds a development tool to edit, inspect and generate XPath 1.0 expressions, CSS 3 selectors and JQuery selectors (Sizzle selector engine).
Pearl Crescent Page Saver screenshot tool Requires Restart
Save an image of a web page (including Flash content) to a file. Web page screenshots may be captured interactively or from the command line. Options allow you to control the output format (PNG or JPEG), image file name, scaling, and much more.
RequestPolicy Requires Restart
Be in control of which cross-site requests are allowed. Improve the privacy of your browsing by not letting other sites know your browsing habits. Secure yourself from Cross-Site Request Forgery (CSRF) and other attacks.
Wappalyzer is a browser extension that identifies software on websites.
HttpFox Requires Restart
An HTTP analyzer addon for Firefox
A very simple extension for learning web page colors. Copy the RGB or Hex color code of any pixel displayed in your browser to the clipboard (in CSS/HTML format). Similar in function to Internet Explorer's color picker.
RefControl Requires Restart
Control what gets sent as the HTTP Referer on a per-site basis.
Clear Cache Button Requires Restart
Adds a clear cache toolbar button. After installing the extension, find the clear cache button in the toolbar customization...
IE Tab + (FF 8+, 7, 6, 5, 4, 3.6, 3.5, SeaMonkey) Requires Restart
IE Tab + is an enhanced version of IE Tab. It supports FF 3.5 or greater, integrates IE Tab with Adblock Plus in the IE Tab engine, and synchronizes cookies between IE and Firefox. You can easily import settings from the original IE Tab into IE Tab +
Override browser user agent string
Manages the Remote XUL whitelist to allow websites and local files to load XUL content. For versions compatible with Firefox 41 and lower, see All Versions page below.
YSlow Requires Restart
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.
User-Agent Switcher Featured
Quickly and easily switch between popular user-agent strings.
CacheViewer Requires Restart
This extenion is GUI Front-end of "about:cache"...
URL Fixer Plus RU and UA Requires Restart
Extended URL Fixer for RU and UA
Accelerate your SEO efforts on the fly. SEOquake is a free plugin for browsers that provides you with key SEO metrics for a specific page, along with other useful tools such as SEO Audit and many others.
IE View Requires Restart
Lets you load pages in IE with a single right-click, or mark certain sites to *always* load in IE.
Fire IE (FireIE, Enhanced IE) Requires Restart
Embeds Internet Explorer(IE) to use the powerful Firefox add-ons.
Not only an enhanced IE Tab, but also an enhanced Internet Explorer with Adblock Plus and FireGestures support.
Switch to the IE engine in one click and dismiss your IE.
Custom Buttons Requires Restart
Gives a possibility to create custom toolbarbuttons...
JS Print Setup Requires Restart