Since nvidia drivers do not properly implement implicit sync, this protocol not existing is the root cause of flickering with nvidia graphics on Wayland. This MR being merged means that Wayland might finally be usable with nvidia graphics with the next driver release.
We also need support for the new protocol in Nvidia’s driver. Support will be available in driver 555, the beta of which will be released on May 15. So there’s still some time to wait until it’s fully fixed.