Upstream publishes .debs as part of their release process. I doubt they conform with policy, but here's their metadata:
https://github.com/koreader/koreader/tree/master/platform/debian Bizarrely, their control file is hidden in a shell script: https://github.com/koreader/koreader/blob/master/platform/debian/do_debian_package.sh#L47 -- What people say, what people do, and what they say they do are entirely different things. - Margaret Mead
