We spent a good 5 or 10 minutes thinking we were crazy. "I'm sure the option used to live here..."
As ever, Google came to the rescue..
Why did Mozilla do this? Because of "Checkboxes that kill your product".
Unfortunately, as a tester I still experience moments where I need to kill the product, so How can I do that now?
Add-onsOne of the official forum Q&A items mentions an add on called QuickJava, just make sure that enable the "Add on bar" from the toolbar menu "View \ Toolbars \ Add-on bar"
Other plugins mentioned in this other official forum Q&A item
I chose to install QuickJava because it lets me toggle a bunch of things quickly.
But hey ho. Testers have had it worse - remember when we used to have to same html to the desktop to edit it? And edit actual cookie files? We have it easy - particularly when you get to discover a new helpful add-on that you didn't know about - QuickJava.