@amadeus I wouldnt be so sure...

My tests on https://github.com/falkTX/wayland-audio-plugin-test/ show it is possible, and based on that I could easily support wayland UIs in Carla (not the S1 spec though, please let's not do their proposal as it would complicate hosts job way too much)

afaik that repo contains the very first LV2 UI under wayland. granted it does nothing useful, but it does load with its own custom LV2 UI type