After being under discussion since January of 2024, the ext-background-effect-v1 staging protocol proposal by KDE developer Xaver Hugl has finally been merged to the Wayland-Protocols repository. This new Wayland protocol is intended for handling effects like background blur on terminals.

Xaver Hugl explained in the year-old merge request for ext-background-effect-v1:

"This protocol allows the client to specify a region behind the surface that should be blurred, with the intention to improve the visuals of for example panels or terminals.

This protocol is roughly based on the org_kde_kwin_blur protocol, which has been in use since 2015. The protocol is made more generically though, so that other related effects can be added in the future, like for example contrast improvements."

The initial ext_background_effect_v1 protocol specification is focused on applying a blur effect to a background / screen region but can be extended for other effects moving forward.