The penumbra of open source: projects outside of centralized platforms are longer maintained, more academic and more collaborative

GitHub has become the central online platform for much of open source, hosting most open source code repositories. With this popularity, the public digital traces of GitHub are now a valuable means to study teamwork and collaboration. In many ways, however, GitHub is a convenience sample. We need to assess its representativeness, particularly how GitHubs design may alter the working patterns of its users. Here we develop a novel, extensive sample of public open source project repositories outside of centralized platforms like GitHub. We characterized these projects along a number of dimensions, and compare to a time-matched sample of corresponding GitHub projects. Compared to GitHub, these projects tend to have more collaborators, are maintained for longer periods, and tend to be more focused on academic and scientific problems.