Update Material 3
The Material 3 update in QcQtuickControls removed lots of stuff, which breaks our bundled Kirigami/Material/Theme.qml in lots of interesting ways. It needs to be updated.
Turns out, most of those properties were not even documented, thus they were considered private, and were allowed to break between minor releases. Interestingly, Material implementation of controls uses that "private" API quite a lot, including a very useful function:
color: control.Material.buttonColor(control.Material.theme, control.Material.background,
control.Material.accent, control.enabled, control.flat, control.highlighted, control.checked)
…which handles most of the conditional logic in fast C++ code.