"What are my options if I want to install unsigned extensions in Firefox?
The Developer Edition and Nightly versions of Firefox will have a setting to disable signature checks. There will also be special unbranded versions of Release and Beta that will have this setting, so that add-on developers can work on their add-ons without having to sign every build."
- Special version of the software
- Can't run my own version of AMO
You can, AMO is open source: https://github.com/mozilla/olympia
Run your own instance and make your own builds of Firefox that point to it and you're good.
Yeah, let me just get all of the potential users of my AMO alternative to compile a custom version of Firefox for it
https://addons.mozilla.org is an integral part of Firefox, if you set it up with an alternative you're effectively making your own fork.
And no, I'm not in a corporate environment. I'm talking about decentralization.