﷽ <- the single codepoint the author is talking about.

It's pretty great fun pasting it into various text entry fields to see how they behave.

In standard-ish single-line-ish Apple text fields on my Mac (iMessage text entry field, Chrome Omnibox), it renders like this, which... I'm not sure is correct? https://cleanshot.com/share/0GkNJGQ7

On the other hand it renders akin to Chrome in TextEdit.