[dfox]

Cut buffers are different thing than selections and cut buffers are deprecated and probably not used by anything written in last 25-30 years.

On the other hand cut buffers are so simple that there isn't any of the complexity as with selections. But still I think that the ICCCM/Wayland model of selections is the only sane way how to implement clipboard, because it does not involve creating some kind of shared state of potentially unbounded size and consuming potentially unbounded CPU time doing that even if it will not be used.