I managed to avoid disappearing down a rabbit hole yesterday.
Initially, I was looking at how to make RSS feed fetching more efficient but ended up looking at ActivityPub and thinking "it would be cool to add this to the blog."
A quick glance at the spec and some existing PHP implementations scared me off. I think it's way beyond my ability. I know I said that with webmentions but this is some next level shit.
Thinking about it, considering that I don't use federated systems like Mastodon, I think it would be a waste of effort for minimum gain.