msgrel — A related component of a message in a message set
Related messages are usually messages that appear elsewhere in response to the same event (or set of events) that triggered the main message. For example, if a network client produces a failure or warning message, a related message might appear on the server console.
May be formatted inline or as a displayed block, depending on context. Sometimes suppressed.
On the whole, the semantics of
MsgSet are not clearly defined.