flatpak builder error

I’m trying to build a flatpak application from this github repo:

I’m posting it here because it seems to be related to opensuse.

So when I build it, this happens: https://pastebin.com/SeT0tMnW

However, when I build it in CentOS, the last output is very similar, except for the last error line.

Is there anyone here with some more flatpak/opensuse experience that can help?

Please use Code-Tags for terminal output:

And ever with the complete commandline.

Thanks for the suggestions, but the complete log was over the character limit for the post, so I couldn’t use the CODE tag.
The first line is the complete commandline.