Is there any way to see which instances are federated with each other?
Title, basically.
Unless admins of specific instances are publishing defederation lists, it seems like it's impossible to tell without visiting a community on a defederated instance from your home instance only to see "no posts." While I like federation overall, I feel like most users are going to end up with a few accounts or setting up their own Lemmy instances just so that they can see stuff from all other instances without running into errors.
Maybe adding some sort of message when viewing a community from an instance not federated with it would be a good idea, with a generic catch all of "Your home instance is not federated with the instance that this community is on. Please contact your instance administrator for details" with the option for instance admins to customize the message per instance if they want to. I'm not really a programmer-type so I wouldn't know if that was even feasible.
@Rikudou_Sage has the answer to see which instances are linked and blocked by any particular instance
defederating/blocking is not bilateral – instance A can block instance B without instance B blocking instance A
federating/linking is initiated when you search, browse, or subscribe to another community from your home instance – no need to send a request to your admin
even then, you still won’t see anything from instances your instance has blocked – which is why it is important to pick a home instance whose policies you agree with
Keep in mind with 0.18.3 there is a new "dead server" check that cuts off communication that won't show up on the block list. There have been reports in !fediverse@lemmy.ml recently that this has caused some issues. notable posting: https://lemmy.ca/post/2626714