The invent link is https://invent.kde.org/unmaintained/kvkbd, but that's no different to the github repo.

The code is still on KDE4 level and doesn't have any kind of Wayland support. Without that it would be a non-starter. Technically it should be possible to implement input_method_v1 (like Maliit does), but I'm not sure this is really suitable for such a keyboard. Perhaps https://wayland.app/protocols/virtual-keyboard-unstable-v1 would be more suitable, but KWin currently has no support for it

@nicolasfella Thanks for the details! Looks like this needs a bit of work before we can include it.