Since code revisions reflect the extent of human involvement in the software development process, revision histories reveal the interactions and interfaces between developers and modules. We therefore divide developers and modules into groups according to the revision histories of the open source software repository, for example, sourceforge.net. To describe the interactions in the open source development process, we use a representative model, Legitimate Peripheral Participation (LPP) , to divide developers into groups such as core and peripheral teams, based on the evolutionary process of learning behavior. With the conventional module relationship, we divide modules into kernel and non-kernel types (such as UI). In the past, groups of developers and modules have been partitioned naturally with informal criteria. In this work, however, we propose a developer-module relationship model to analyze the grouping structures between developers and modules. Our results show some process cases of relative importance on the constructed graph of project development. The graph reveals certain subtle relationships in the interactions between core and non-core team developers, and the interfaces between kernel and non-kernel modules.