While version 2.3.0-3 of knowthelist was never uploaded, it still appears in the changelog which might be a bit misleading. Also the bug #799710 may be left accidentally open, because by default, only the topmost changelog entry contributes to automatical closing of bugs (via the field "Closes:" in a .changes file,
https://manpages.debian.org/unstable/dpkg-dev/deb-changes.5.en.html ).
For this reason I recommend that you don't have a separate entry for an unreleased upload.