How to get back the old debugger in Firefox
Firefox 52 introduces a new JavaScript Debugger with new UI but lack of many features that the old one has. One that I found critical and can't work without is the ability to search for some text in all files. So how can I get back the old debugger?
If you're using Firefox 52 or later and need to switch back to the old Debugger, you can do so by visiting about:config and setting the devtools.debugger.new-debugger-frontend preference to false as explained on MDN.