Wayland-Protocols 1.21 Released With XDG_Activation, Staging Replaces Unstable
With Wayland-Protocols 1.21 the XDG_Activation protocol has been introduced. This protocol is for transferring focus between top-level surfaces such as from a launcher to launchee.
XDG_Activation has been in the works since last year and already has pending support for Qt Wayland, KWayland/KWin, GNOME's GTK and Mutter, WLROOTS, and more. The XDG_Activation protocol was authored by both GNOME and KDE developers as a way for a client to pass focus from a top-level surface to another. The specification text in full can be found here.
With the protocol now part of Wayland-Protocols 1.21, the XDG_Activation support on the KDE side was already merged.
Wayland-Protocols 1.21 is also changing the terminology of new "unstable" protocol to instead refer to it as a "staging" protocol.
Wayland-Protocols 1.21 also now has support for installing it using the Meson build system as an alternative to Autotools.
More details on the 1.21 update and the contained fixes via the release announcement.