Free and Open Source Software (FOSS) is widely reused today. To reuse FOSS one must accept the conditions imposed by the software license under which the component is made available. This is complicated by the fact that often FOSS packages contain files from many licenses. In this paper we analyze the source code of packages in the Fedora Core Linux distribution with the goal of discovering the relationship between the license of a source package, and the license of the files it contains. For this purpose we create license inclusion graphs. Our results show that more modern reciprocal licenses such as the General Public License v3 tend to include files of less licenses than its previous versions, and that packages under an Apache License tend to contain only files under the same license.