I noticed this also. It is caused by the platform detection code that I use. https://github.com/Sude-/lgogdownloader/blob/master/src/downloader.cpp#L2053-L2064
It tries to speed up the detection of supported platforms for games by looking for platform identifier in the game shelf HTML. This fails because for some reason the 'data-title' attribute for Pillars of Eternity doesn't have Linux in it (and it is also missing Mac).
I have written a patch that allows skipping the fast platform detection. I'll commit it as soon as I've cleaned it up.
edit: committed 3834c1e
Add option to skip fast platform detection
Your responsiveness is amazing. :)
I installed from source originally using the Makefile in lgogdownloader-2.20.tar.gz source archive. I noticed it putting things like the manual around the system when I installed it, and I don't want any conflicts.
Do I need to remove the old installation before installing the new one? How?
Edit: I should have read the Makefile before posting.
Still not sure whether removing it was necessary, but I did the following:
sudo make uninstall
git clone https://github.com/Sude-/lgogdownloader.git
sudo make install
and yes, it is now working with the --no-platform-detection flag.
Thanks for sharing your good work Sude.