Even today, every new feature you want to have in the WebExtension API needs to be implemented as a legacy extension providing this API first, then it will get tested, and then it will maybe become part of core Firefox.
The official process to add apis for WebExtensions is to write a legacy extension.
Which is exactly what I'm doing to support my custom extension that replaces the entire history and bookmarking system, UI and toolbars of Firefox, for which I need a custom API.
I suggest you read the wiki on why nightly still supports legacy extensions before judging people.
I'm not judging I wrote that everyone has it's own use case. My only point is don't use test version if you don't want to be tested or opt-out of it. ;)
Even today, every new feature you want to have in the WebExtension API needs to be implemented as a legacy extension providing this API first, then it will get tested, and then it will maybe become part of core Firefox.
The official process to add apis for WebExtensions is to write a legacy extension.
Which is exactly what I'm doing to support my custom extension that replaces the entire history and bookmarking system, UI and toolbars of Firefox, for which I need a custom API.
I suggest you read the wiki on why nightly still supports legacy extensions before judging people.