Wireless Sensor Network (WSN) software is typically developed in one of the two prominent WSN operating systems: TinyOS or Contiki. Both of these operating systems are open-source projects and basically frameworks for WSN developers. In this paper, we study the software repositories of these two projects. Software repositories provide a wealth of information on software projects and their development. Based on the mined information, we explore the TinyOS and Contiki commit history and compare them to an open-source embedded operating system, Ethernut. As a second step, we explore WSN-specific artifacts and mine TinyOS software for cross-cutting concerns. Most of the relations we find are not cross-cutting. Nevertheless, we do find cross-cutting concerns that are resource-related.