Here is a paper about how PLT Scheme’s package repository, PLanetT was designed. PLanetT is a the PLT Scheme equivalent of CPAN.
For the past two years we have been developing PLaneT, a package manager built in to PLT Schemes module system that simplifies program development by doing away with the distinction between installed and uninstalled packages. In this paper we explain how PLaneT works and the rationales behind our major design choices, focusing particularly on our decision to integrate PLaneT into PLT Scheme and the consequences that decision had for PLaneTs design. We also report our experience as PLaneT users and developers and describe what have emerged as PLaneTs biggest advantages an drawbacks.
(mentioned in this post PLT)