A discussion relevant to UTS 51: Unicode Emoji is occurring in the W3C’s CSS Working Group on GitHub at https://github.com/w3c/csswg-drafts/issues/2138.
To review, the Consortium recently registered several BCP47 language-tag extension keys for specifying transliteration and text-vs.-emoji presentation such as “en-u-em-emoji” (see http://blog.unicode.org/2016/03/cldr-version-29-released.html). Basically, the W3C and the major web-browser vendors are considering normatively forbidding any influence of Unicode’s BCP47 extensions on the presentation of emoji characters in HTML and XML, viewing them as currently little used and fully redundant to variation-selector characters and the CSS font-presentation property. The Consortium was the the originator of the BCP47 extensions and may have insight into their use cases; thus, those involved in registering the extensions may be interested in participating in this discussion, which is occurring on GitHub at https://github.com/w3c/csswg-drafts/issues/2138. So far, representatives from Google Chrome / Blink (Sascha Brawer), Microsoft Edge / Chakra (Sergey Malkin), Apple Safari / WebKit (Myles C. Maxfield), and W3C (Chris Lilley) have been participating. J. S. Choi
