@BeAware@social.beaware.live @ThaMunsta@nervesocket.com From glancing through the github issues it looks like it only does that for account deletions. Though I have no idea how many of these are resolved or no longer function as described in the issues

https://github.com/mastodon/mastodon/pull/22273:

One outstanding issue with Mastodon is that deleting a local account sends a Delete activity to the whole known fediverse to ensure everyone is aware that the account does not exist anymore. This is wasteful, and increasingly so with the growth of the fediverse. It is also a minor privacy concern, as servers who would otherwise not know about an account would learn about its (previous) existence without a good reason.

https://github.com/mastodon/mastodon/issues/22154

Currently, posts deleted over a week earlier on one server are still visible on others. For example, I can see (on both mastodon.social and mstdn.social) a post I deleted at the start of December on mstdn.jp. On both of those other servers, it looks like the post is still live and available on mstdn.jp.

https://github.com/mastodon/mastodon/issues/22070#issuecomment-1340711206:

To clear up some misunderstanding, Mastodon does not send a Delete to every known server for every deleted post, that would be too expensive. It does send a Delete to every known server for every deleted account though.
I do have some idea on how to improve that (keep track of which servers ever requested an account, using a bloom filter so it remains manageable storage-wise), but it will require some work and will only work for newly-created accounts, not ones that existed before the change was implemented.

https://github.com/mastodon/mastodon/issues/6849#issuecomment-1418688876

It’s retried a bunch of times, but once every retry is elapsed and the post is deleted, Mastodon stores neither the post’s previous existence nor who was supposed to see it, so such a feature would require the admin to provide:
the post’s author
the post’s exact ID
who to send the deletion notice to