[talklittle]

Firefox Test Pilot [1] is a more recent approach to testing new UI in Firefox. It's entirely extension based. I think this is a smart approach because it lets Mozilla quickly test new UI features without building it into the core browser before it's been vetted.

However its full potential is not ready yet, since Firefox has been migrating to WebExtensions, and this has not fully stabilized yet. Long term I think the WebExtensions move also makes sense, since it gives extension authors a stable API to work with, instead of XUL which can break with each Firefox update. And the architecture makes it easier to optimize threading performance and some form of security sandboxing.

So the point is, I think more UI experimentation is on Firefox's horizon, but they have to first stabilize the technical architecture before they can go full throttle on that.

[1]: https://testpilot.firefox.com/

[anigbrowl]

I'll give it a whirl, thanks for the tip!