The Wiz post has significantly changed since it was first published (and how it looked when first posted to HN), FYI -- see [1]. When it was published, it was a summary of the React announcement, and was somehow longer than the original and yet provided less useful information than the original.
In any case, the "tell" is the syntactic structure (as Chomsky would say) and certain phrases used in the post.
[0]: https://news.ycombinator.com/newsguidelines.html
[1]: https://web.archive.org/web/20251203162416/https://www.wiz.i...