Hi,
here comes the solution.
I did not find this myself. The honours go to Zompel of the German Manjaro Forum who did the job of researching and finding out.
You have to install
libwpg (library for importing and converting WordPerfect Graphics format), using
sudo pacman -S libwpg
or:
pamac install libwpg
Once this item is installed, LibreOffice will be capable of opening AppleWorks, ClarisWorks and pages text files.
That’s all, really. Don’t ask why this is so. I don’t know either what a converter for WordPerfect Graphics has to do with Apple text files – but it works.
If anybody is interested in more details, I will gladly furnish them.
Peter