So far so good. I needed an extension to edit cookie values since Firefox Quantum removed this functionality from the F12 developer toolbar, and since Google recently changed its privacy opt out mechanisms (see Personal info & privacy > Tools you can use now) to expire opt-out cookies after random short durations (30 minutes or less in some cases) and randomly 'forget' certain opt out settings. This extension did the trick. I am not happy with FF Quantum's all-or-nothing privacy permissions but that's not the fault of this developer -- I appreciate the transparency of this developer in explaining why such broad permissions are needed by the extension.