Funkwhale uses a dedicated service actor to send messages or authenticate fetches. This actor isn't associated to a user.
You can query a pod's nodeinfo endpoint to return the ID of the service actor in the
metadata > actorId field. See the API explorer for more information about this endpoint.
Funkwhale considers a pod's service actor to be an authoritative source for activities associated with all objects on its pod's domain. If the service actor sends an activity linked to an object on its domain, remote pods will recognize its authority.