spFilterWebContent от terriskator

This extension allows the user to watch the requests sent by Firefox. After a click on the icon of the extension a new tab is opened which shows all requests. The user can check the output for unwanted requests.

In the options page the user can specify which requests should be blocked, what request headers should be shown in the console and what font should be used.

The extension blocks requests in the following way:
First it checks if one of the strings in the option value "URL" is part of the URL. If yes, the request is blocked.
For webquests of type SUB_FRAME, IMAGE, IMAGESET, SCRIPT, STYLESHEET, FONT the additional option values for these types are also checked.