Hi!
I have debugged this, and this is indeed AI bot protection from
Codeberg. Funnily enough, if you are suspicious enough, you will
actually receive an image back at the right size, but with a nonsense
QR code on it. This sucks for AppStream, because it is actually a very
well-behaved downloader - fortunately though, Codeberg lets us pass if
we also tell it that we are using libcurl and our curl version. So
this issue is resolved. I also extended the generator to identify the
content that it has received and tell whatever that was in its error
message.
The only project affected by this bug was backintime-qt, however, it
improved the warnings on various other packages, so this is a win.
The changes are live on appstream.d.o, I will close this issue once a
package that contains this fix actually lands in Debian (currently,
the changes are only in Git and not yet released).
The backintime-qt package now has no hints at all, which is a very good sign.
Best,
Matthias
