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.
EDIT: Nvidia dev posted that support is planned in the 555 driver, with beta release planned for May 15: https://github.com/NVIDIA/egl-wayland/pull/104#issuecomment-2010292221
Engineers are made to do things they don’t want to do, not their fault but they don’t really have the power to do things properly