@ubernigga @lina @Cyrillic Lets instance admins differentiate from where the request is coming. If instance A fetches a post from instance B but doesn't sign it with its own key or is blocked on instance B, the request is discarded, meaning users on instance A won't be able to see it despite the fact it was posted in public scope and could be viewed in browser from other instances. So it breaks federation while offering nothing but a drop of peace of mind for neurotic troons. But if you think instance A can pretend to be instance C to circumvent it, you'd be right; so it's not even secure in any way.