发布的Android支持库有哪些许可证？

I've been reading through the documentation for the Android Support Library, but while it explicitly says that you should include it in your Android project, it doesn't mention anything about what license the library itself is under (the only license notice present applies to the contents of the documentation page, not the code it describes). The copy spat out by Eclipse does not include any licensing information either, and queries to Google mostly just link back to the same documentation pages. for