I first started writing about libwebrtc source management, build and test systems almost 5 years ago. While the posts are still here, and mostly accurate, people forget, and/or the system as changed just enough that we need to update what is the de-facto reference for libwebrtc. As we are writing a book, with examples and illustration to be used in classrooms to teach the underlying principles, and in companies for e.g. on boarding Engineers, we though we should put some extract here.