> Additionally, the Wayland protocol carries an event identifier, so that the compositor can tie the clipboard request to a pointer/keyboard/touch event and take a better decision.

That's actually not the case. There's a serial number that the client provides when they want to set the selection (that is, cut/copy)[0][1], but nothing when a client requests a paste[2][3].

I always thought this is weird; while yes, it's nice to prevent random applications from spuriously taking over as the source of the clipboard/primary, I think it's much more important to have a mechanism to reduce the risk of a client pasting without permission.

[0] https://wayland.app/protocols/wayland#wl_data_device:request... (regular clipboard)

[1] https://wayland.app/protocols/primary-selection-unstable-v1#... (primary selection)

[2] https://wayland.app/protocols/wayland#wl_data_offer:request:... (regular clipboard)

[3] https://wayland.app/protocols/primary-selection-unstable-v1#... (primary selection)