It's a property of 02packages.details.txt. This file maps module to distribution names (and versions), and so if a module in one version of a distribution gets dropped (or renamed) in a later version of the distribution, 02packages.details.txt will have two versions of the distribution. eg, for Zanas: Zanas 0.9954 D/DM/DMOW/Zanas-0.9954.tar.gz Zanas::Dawdler undef D/DM/DMOW/Zanas-5.3.25.tar.gz Zanas::Docs undef D/DM/DMOW/Zanas-5.3.25.tar.gz Zanas::InternalRequest undef D/DM/DMOW/Zanas-5.3.25.tar.gz Zanas::Loader undef D/DM/DMOW/Zanas-5.3.25.tar.gz Zanas::Request undef D/DM/DMOW/Zanas-5.3.25.tar.gz Zanas::Request::Upload undef D/DM/DMOW/Zanas-5.3.25.tar.gz