> that's why they've killed XUL
We couldn't deliver a multiprocess browser without doing it.
> about:config for the android version
I completely supported this and continue to do so. GeckoView on Android works completely differently than desktop Firefox, and about:config's semantics are not identical between the two. A few of us were interested in offering an alternative that gave users a way to make adjustments in a way that was "safe," but as you can imagine that has never been a management priority.