The link goes to Palemoon forums, and it says that the requested topic doesn’t exist.
I think it’s because they want to have more control over their hardware than Microsoft lets them.
It’s gaining momentum, so I don’t think it will decrease.
It’s a big boy.
The proposal looks a lot like what KDE is to me. Some ideas I agree with, like the use of applications that work together in a UNIX way, but I don’t agree with the point that the UX/UI trends of 2010s have regressed the usability of the desktop. Flat design makes things a lot more recognizable and provides a clean workspace and workflow. Also, there is a thing that’s too many customizability. Users can feel burned by the amount of things you can customize, and the vast majority of them don’t even change their desktops from the default settings.