Ktouch Typing Lessons License

Hello,

I am the maintainer of GNU Typist and we are trying to (re)integrate
the Ktouch typing lessons into our project.

For that I need what license applies to the files, if it is compatible
with GPL3+. Does anyone here know?

Here are the files in question:
https://invent.kde.org/education/ktouch/-/tree/master/data/courses

Previously, I emailed the authors and I tried to contact people on IRC
or webchat, but I didn't find an answer. Eventually I was pointed here.

Thank you,
Mihai G=C4=83tejescu