CommonMark is the "standardized" version, isn't it?
https://blog.codinghorror.com/standard-markdown-is-now-commo...
Jeff Atwood goes out of his way to be courteous to Gruber in this post, but frankly, I think Gruber was being a jerk here, using his claim to the name to tyrannise an open source community that he has otherwise not been involved with in the slightest the last ~17 years.