Less than a month ago, HTML 5.2 became an official W3C Recommendation (REC). When a specification reaches the REC stage, this means that it has received the official endorsement of W3C Members and the Director, and that the W3C officially recommends it’s deployment by user agents, and it’s implementation by web page authors. By the REC stage, anything new should have had at least 2 independent implementations [https://www.slideshare.net/rachelandrew/where-does-css-come-from/27?src=clipshare] .