This account is a virtual actor used to represent the server itself and not any individual user.
It is used for federation purposes and should not be blocked unless you want to block the whole instance, in which case you should use a domain block.
Moderated servers
Mastodon generally allows you to view content from and interact with users from any other server in the fediverse. These are the exceptions that have been made on this particular server.
Silenced servers
Posts from these servers will be hidden in public timelines and conversations, and no notifications will be generated from their users interactions, unless you are following them:
