This field shall indicate the MessageID for the message being confirmed.
Optional
replyThis field shall indicate a user-provided reply to the message. If there was no reply, or the message did not have the ReplyRequired bit set, this field shall be null.
Optional
responseThis field shall indicate the MessageResponseID selected by the user. If there was no response before the Duration of the message has elapsed, this field shall be null.
Body of the Messages messageComplete event
See
MatterSpecification.v13.Cluster § 1.16.8.3