[WorldMaker]

This seems to me like an improvement for systems that don't have blockquotes in their embedding source (previously the behavior was that if there was no HTML inside the embedding element there was no fallback at all and it was just an empty element) that was an accidental regression.

I hope they add a simple check if the element has children or not to fix the regression, but I work on an app where some sort of fallback UI for deleted Tweets is a welcome change, even if "blank Tweet card" isn't a huge improvement, it's still a small win to get some hard-to-fix-on-our-side UI complaints off the backlog.