I have a package (kadu) which uses Qt but namcap will not detect it (and it's not like this dependency is covered indirectly). I think I know the reason. Some of kadu's dynamically loaded modules depend on kdelibs. Since kadu runs fine without kdelibs, I did not include kdelibs in depends (and namcap of course complains about it). I guess when namcap detects the Qt dependency, it takes also kdelibs into account and after complaining about missing kdelibs, it doesn't see necessary to inform about Qt which in my opinion is wrong.