While I was initially pretty shocked that Mozilla would make a walled-garden move like this, doing it on the mainline release (for a primarily non-technical audience) and not holding the same requirement on dev and nightly builds actually feels like an appropriate balance, if that is indeed accurate.
Probably near 100% of Tridactyl users would be comfortable on at least the dev version of FF; it may be that an appropriate remediation would be to offer the `fixamo` functionality on an unsigned extension release only.
1. Signing is required via a compile-time flag for official builds of Firefox and Firefox Beta.
2. Signing is optional in other builds of Firefox (Unbranded, Developer Edition, and Nightly), and follows the `xpinstall.signatures.required` user preference.
3. On Linux, add-ons installed in `/usr/{lib,share}/mozilla/extensions` are exempt from signing.
4. Add-ons manually loaded via "Load Temporary Add-on" in about:debugging are also exempt from signing.
It's accurate. Mozilla's intention was that Firefox couldn't be exploited by malware installing dodgy extensions, thus they want most people's installs of Firefox to reject unsigned extensions. But people who know what they're doing are free to download unsigned unbranded builds.
FWIW, I tried the dev edition (which is essentially Firefox beta) but I stopped using it as I kept running into bugs. A release that wasn't more buggy but allowed unsigned extensions would be nice.
I have been using exclusively dev and nightly for at least two years, and have only very occasionally run into issues. Of course, my usage is pretty typical web browsing, outside of using the dev tools.
It’s been long enough now that the normal colorful Firefox logo seems weird.
Probably near 100% of Tridactyl users would be comfortable on at least the dev version of FF; it may be that an appropriate remediation would be to offer the `fixamo` functionality on an unsigned extension release only.