stefan, 
So Mastodon has an "instance/peers" endpoint that lists "domains that this instance is aware of".
https://docs.joinmastodon.org/methods/instance/#peers
Example: https://mastodon.social/api/v1/instance/peers
I'm playing around with this a bit, and looking at one instance that knows about mine, but I can't find my own posts or my account on it.
Is this expected behavior?