It's not at all baffling seeing the recent history of firefox dealing with extensions.
Back in the day, when xul extensions were the way to go, things were great, for years the api was reasonably stable.
Then xul extensions were to be replaced by things created by the addon-sdk. To make things more interesting the addon sdk used a python based tool first, later to be replaced by node-js tooling. So (minor)rewrite needed, even though legacy xul extensions still worked as well.. But not for long, noo, for no good reason (because there was already talk of webextensions in firefox), extensions suddenly had to be signed and often MANUALLY reviewed, xul no longer allowed, perfectly fine extensions would not pass automatic review and would not be manually reviewed for no other reason than using legacy code that was hard to review.
So this meant extensions had to be rewritten to use the addon-sdk and jump through hoops to avoid using javascript libraries that caused the automatic review process to break. This all happened a good year ago.
Now, all these addon-sdk extension have to be rewritten once again, because webextensions.
This whole extension review process for addon-sdk, imho, should never have happened and should simply have been postponed till webextensions are ready (they aren't now, they are buggy as hell, yet currently extensions have to be webextensions in order to be published...). As a matter of fact, the whole addon-sdk should never have happened and mozilla should have moved to webextensions immediately.
To me firefox greatest strength was how moddable it was. Not only is this advantage lost by moving to webextensions, the horrid process from xul to addon-sdk to signing and broken review to webextensions must have cost them much goodwill from extension devs. And yes, it has tainted my view on mozilla, i think they honestly mean well, but they desperately need better management that doesn't jump on any hype laden bandwagon, right now they seem to be pushing out new toys that are watered down half functional versions of what used to available. Google might have a name to abandon their projects, i now have the same level of fate in the continuance of any mozilla project.