No, I believe it is the case that Gruber conflated two separate projects (which might both be part of the same overall vision). The first was codenamed "Marzipan" and has been announced (and leaked and reported by Gurman). The second is what Gruber is speaking of in that article, and relates to laying out views. It has not been announced, but is codenamed Amber. Gruber clarified this post-Marzipan announcement in a tweet [0]. More info from Gurman [1].

[0] - https://mobile.twitter.com/gruber/status/1014490721909444608

[1] - https://mjtsai.com/blog/2018/05/01/scuttlebutt-regarding-app...