SettingSanity is a solution to the inane removal of some of the most useful features in Firefox. It also adds the option of toolbar buttons for toggling Images and JavaScript without opening your preferences, as well as some helpful tab settings at the request of many users. Supports Firefox 56. In the meantime, after reinstalling 51.0.1, I've spent a day trying to find a good replacement that offers something similar to Classic Theme Restorer, settingsanity (both of which I 've been forced to use since the last time you decided to 'do what is best for Linux and Firefox'), cliget and Kitsune.
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Specifically, wanted features include:
Turn images on/off globally in the browser
Turn images on/off in the current tab
Create exceptions for specific URL strings, like Firefox had before 'progress' killed it. E.g., I had an exception for google image search's 'gstatic' URL, so thumbnail images in google image search results always displayed.
I'm also looking for something similar for stuff like flash, java, and javascript. I know the Developer Kit will let me turn styles on and off, and possibly flash/java/javascript, but I'm looking for something simpler and quicker, that works more like QuickJava did for Firefox, before 'progress' killed it.
I'm not optimistic, but I figure it can't hurt to ask.