Oh interesting, I've never liked Firefox. It never works right for me and everything connected to it gives me problems by association 😅 I don't understand why the additional "-" tag would make a signer extension fail, though. It's just a tag, right? But maybe thats above my pay grade. Glad you figured out a solution for now.

I would like to suggest looking into ncryptsec though. You can encrypt with Amethyst and Hallway supports it. Pretty sure Pyramid does, too, but I'm not in a position to double-check at the moment.