Nordnick, apparently something as trivial as the requirement of JDK 17 is a showstopper for them and now we gotta wait approximately one eternity for them to update the Debian image for their CI container... Because, of course, downloading a .deb file with prebuilt OpenJDK and installing it as part of the build script is also a non-starter, for reasons.
https://gitlab.com/fdroid/fdroiddata/-/merge_requests/10909