The KDE Plasma experience with Wayland has reached a level of maturity where it makes sense to switch it to the default session.
With this change, the "Plasma (X11)" session is deprecated, slated for removal in a future version of KDE Plasma.
This merge request is based on feedback from a discussion with @ngraham, @davidedmundson, and others at Akademy about X11 and Wayland support timelines.