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User Agent Switcher Requires Restart

The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.

Rated 4 out of 5 stars (336)
2,570 weekly downloads

SQLite Manager Requires Restart

Manage any SQLite database on your computer.

Rated 4 out of 5 stars (354)
2,313 weekly downloads

Element Hiding Helper for Adblock Plus

Fight the text ads! Element Hiding Helper is a companion extension for Adblock Plus meant to make creating element hiding rules easier.

Rated 5 out of 5 stars (473)
1,322 weekly downloads

Live HTTP Headers Requires Restart

View HTTP headers of a page and while browsing.

Rated 4 out of 5 stars (216)
1,037 weekly downloads

NoRedirect Requires Restart

NoRedirect lets the user take control of HTTP redirects. It can be used to interdict an ISP's DNS search redirection hijacks, preview/screen "shortened" URLs (e.g., TinyURL), stop the annoying redirection of "smart" error pages, etc.

Rated 4 out of 5 stars (92)
979 weekly downloads

HttpFox Requires Restart

An HTTP analyzer addon for Firefox

Rated 4 out of 5 stars (217)
940 weekly downloads

Remote XUL Manager

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.

Rated 5 out of 5 stars (36)
841 weekly downloads

Cookie Importer Requires Restart

Imports cookies from a textfile.
Reads Netscape standard cookies.txt files as exported by IE and others.
Very useful in combination with the Cookie Exporter add-on.

Rated 4 out of 5 stars (44)
705 weekly downloads

Classic Toolbar Buttons [Tb24-58] (discontinued)

'Classic Toolbar Buttons' add-on restores old toolbar button ui (known from Fx 4-7 small view, Fx4-12 large view & Tb5-14) for current Firefox, Thunderbird and Seamonkey versions.

Rated 5 out of 5 stars (145)
551 weekly downloads

JavaScript Debugger Requires Restart

As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.

Venkman is the code name for Mozilla's JavaScript Debugger. Venkman aimed to provide a powerful JavaScript debugging environment for Mozilla based browsers.

Rated 4 out of 5 stars (52)
513 weekly downloads

Dafizilla Table2Clipboard Requires Restart

Mozilla applications allow to select rows and columns from a table simply pressing Control key and picking rows/columns with left mouse button.
The selection can be copied to clipboard but the original table disposition is lost making ugly results wh...

Rated 5 out of 5 stars (75)
337 weekly downloads

Stylish Sync

Sync engine for Stylish with backup / restore facility.

Rated 5 out of 5 stars (31)
312 weekly downloads

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.

Rated 4 out of 5 stars (215)
302 weekly downloads

Live HTTP Headers (clone)

View HTTP headers of a page and while browsing.

This is an unofficial "Live HTTP headers" clone, mainly to fix the Replay feature!

Rated 4 out of 5 stars (17)
289 weekly downloads

Linkification Requires Restart

Converts text links into genuine, clickable links...

Rated 4 out of 5 stars (287)
253 weekly downloads

RefControl Requires Restart

Control what gets sent as the HTTP Referer on a per-site basis.

Rated 4 out of 5 stars (180)
245 weekly downloads

DOM Inspector Requires Restart

DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM can be navigated using a two-paned window displaying a variety of different views on the document and all nodes within.

Rated 5 out of 5 stars (77)
228 weekly downloads

Stylish-Custom Requires Restart

custom additions to Stylish extension

Rated 4 out of 5 stars (10)
192 weekly downloads

Proxy Tool Requires Restart

Proxy Tool - Powerful, yet User-friendly proxy tool to manage your proxies and anonymity needs, including: 46M+ user agents (world's largest), 10 different spoofed HTTP referrers, auto-proxy rotation, plus many more. Developed by http://ProxyList.co

Rated 3 out of 5 stars (48)
186 weekly downloads

RequestPolicy Continued

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.

Rated 4 out of 5 stars (28)
175 weekly downloads