Alias_username alias option
alias_username alias option may be used to set the "username" that the MTA will consider to "own" these mailing list messages. (The legacy configuration alias file named parameter equivalent is [USERNAME].) The
imsimta qm utility will allow that username to inspect and bounce messages in the queue resulting from expansion of this mailing list. The
value item should be the username of the account to "own" the mailing list postings.