Seems pretty dead around there, but I submitted a PR to Edit This Cookie with the manifest v3 updates. https://github.com/ETCExtensions/Edit-This-Cookie/pull/373 (and a small hijack since we're on to other tools If you use qmee, I wrote this: https://greasyfork.org/en/scripts/505627-qmee-survey-hourly-rate-calculator)
Thank you for doing that. Your time spent doing this work is quite helpful to me. I think that when version 2 is killed off you will see a lot of people looking for this update. They just don't know they need it yet.
Now that I'm out of the Amazon Payments fiasco: Google requested I remove the unused activeTab and scripting permissions. I was finally able to test it and verify it still works and just re-submitted it to the chrome web store.