Large software projects are often worked on over the course of several years by multiple developers. The history of such projects is typically checked into version control repositories and can be tapped into as a data source for an explorative hierarchy visualization. Our goal was the development of a tool for visualizing the evolution of software repositories. Focus is placed on visualizing a range of time-dependent hierarchies as a whole, rather than looking at individual, isolated snapshots of each timestamp. Hierarchies with attached metrics are derived from the repository at each revision and merged into a supertree, which is mapped using customizable transfer functions and rendered interactively. The tool offers an overview of the entire supertree of a user-defined timespan, while allowing detailed inspection of areas of interest.