I don't know a whole lot on the topic. I have a broad idea. I get the concepts. But I have not bothered to master the details. There are too many versions, too many ways they get done. Android is not fragmented, what is really screwed up and fragmented is how companies get valued.
How companies get valuated reminds me of when they taught me several pre-Charles Darwin theories of evolution at high school. They were all over the place. They all lacked the basic beauty of Darwin's theory of evolution.