CSS Reloader is an extension that allows you to reload all the CSS of any site without you have to reload the page itself.
Fangs renders a text version of a web page similar to how a screen reader would read it. The ambition is to help developers understand how an assistive device would present a website and thereby increase chances of finding accessibility issues early.
Inspect flash(swf)'s DisplayObject with mouse. Overview the swf's DisplayObject list. Set the inspect filter class when use mouse inspect.
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A suite of tools for developers.
The main goal allows users to open (and in some cases edit) page source with external applications.
Latest version is always available at http://dafizilla.sourceforge.net/viewsourcewith
Syntax highlighting for the Firebug command line using Ace.
Fuzzy auto completion
Create and manage add-ons made from Greasemonkey and Scriptish user scripts
Good Website Inspector is an extended ruleset for YSLOW, a Firefox AddOn, to check source codes of HTML pages to get easy and fast hints to optimize the current page.