Because of his new request for an attribution change, the credit line now reads, "This document is authored by the RSS Advisory Board and is offered under the terms of the Creative Commons Attribution/Share Alike license, based on an original document published by the Berkman Klein Center for Internet & Society authored by Dave Winer, founder of UserLand Software."
https://www.rssboard.org/rss-specification
This also includes a change to reflect that the Berkman Center for Internet & Society became the Berkman Klein Center for Internet & Society in 2016.