I suspect that they are downvoting the poster rather than the comment, due to previous posts. I upvoted pron's comment since it was a professional response to the question asked.
46 karma · joined April 17, 2015
“the agreement places a company-wide ban on Android forks, saying OEMs are forbidden from taking ‘any actions that may cause or result in the fragmentation of Android’ and specifically disallows distributing or encouraging a third-party to distribute ‘a software development kit derived from Android.'”
Not so very open after all?
The people who have forked android have great difficulty finding OEMs to manufacture thrir devices as the list of those who don't have agreements with Google is rather short.
EDIT: To answer my own question: http://killercup.github.io/trpl-ebook/