I think an interface that could be defined and iterated on is what Mozilla used to have with their chrome UI specification layer, and I think they mothballed th

I think an interface that could be defined and iterated on is what Mozilla used to have with their chrome UI specification layer, and I think they mothballed that a few years ago? At least I think it was called chrome, it's not exactly easily searchable anymore. Edit: Actually, I think I'm thinking of XUL? I'm not sure how much it's still the standard for Mozilla UI specification or not.