Buttons once again, no longer appear. I've refreshed the page (as that usually causes them to appear) several times, with no luck.

Also, best not to close someone's report unless it's verified that it's working again.

This could also be an issue with Firefox Content Security Policy with respect to Tampermonkey. See a workaround here.

You were right, that fixed it.

Re: @GuyInDogSuit:
Cheers 😊