by "Mozilla approved" do you mean that it has to come from the official add-on store?
because in my experience, it doesn't--I've installed a couple of extensions manually by just dragging the .xpi into the window.
because in my experience, it doesn't--I've installed a couple of extensions manually by just dragging the .xpi into the window.
https://support.mozilla.org/en-US/kb/add-on-signing-in-firef...
I've got one buggy device, but I suspect corruption due to the error message and I'm more interested in saving the unsyncable data I've got on that profile than I am in trying to fix it by clearing data.