Hi Phil, again, thanks for your comments.
I think I was able to fix the reported errors with the exception of an error about the appinfo file: The id in the appinfo file and the name of the appinfo file should be something like "nl.ratrabbit", this is a website I own. However I cannot guarantee that this website will exist for ever, and I don't know how to prove that I am the owner. I see that in /usr/share/meteinfo/ there are a number of other packages that are also not conform, so I guess this is not a big issue. I uploaded a new version of xsnow: https://mentors.debian.net/package/xsnow/ The respective dsc file can be found at: https://mentors.debian.net/debian/pool/main/x/xsnow/xsnow_3.8.0-1.dsc I will try to remove the "moreinfo" tag. Regards, Willem