I would really like to manually add an address, even if it can't be found. Not just be regulated to a picker.
One example, I want to purposefully block lemmygrad.ml. But because lemmy.world defederated from it, it's no longer a valid option. I want to block it at the app level anyways in the event my instance chooses to refedrate.
It's an ActivityPub protocol implementing fediverse platform. It has the equivalent of lemmy's communities which it calls magazines, but it also has microblogging similar to mastadon mixed in.
As a result they sort of work together which is awesome, but also you get stuff like what OP is asking about.