While Bard mentioned a post called Star Star, I couldn't find the quote attributed to John Gruber in it. A search also came up empty. And, many of Bard's other points appear to be nothing more than decompressed garbley gook. However, the referenced post's first sentence answered my initial question: the stars serve as markers for each entry in the Daring Fireball Linked List.
So, what's the Linked List?
The Daring Fireball Linked List is a daily list of interesting links and brief commentary, updated frequently but not frenetically. Call it a “link log”, or “linkblog”, or just “a good way to dick around on the Internet for a few minutes a day”.
Got it, that clears things up. This was a good reminder to verify answers from large language models.