[gsnedders]

I don't know why the parent is voted down; it's a totally reasonable comment.

It's definitely the case that the Firefox UI very much makes it impossible to move away from the current layout implementation at this point, and moving away would be a massive job. At the same time, the Firefox UI cannot move away from XUL/XBL until extensions no longer have free access to it, so this is definitely a first step that's relevant here.

As for using Servo for web content, it's worthwhile pointing out that not only is it the direction Mozilla is taking (with Project Quantum, and progressively moving components from Servo into Gecko), but it would also be a technical challenge because web extensions have access to extra APIs and have security checks disabled in others.