Function relayed 

pub fn relayed(
    actor: Option<SessionId>,
    to: TextTarget,
    text: &str,
) -> ControlMessage

Carry one connection’s words to one recipient.

Which of the three lists is filled is not decoration: it is what the client prints in front of the line, and whether it files the message as private. The identifier put there is the one the recipient holds, never the one the sender named, because the two need not be the same thing here.

actor is None for the server’s own voice, which is what makes the client attribute it to the server rather than to a user it would have to know.

REF: references/mumble/src/mumble/Messages.cpp : msgTextMessage labels the entry Tree, Channel or Private from whichever list is non-empty, and falls back to tr("Server", "message from") when there is no actor. REF: references/mumble/src/murmur/Messages.cpp : msgTextMessage stamps the actor itself and forwards one identical message to each recipient.