When a posted message is being sent to subscribers, the original message header is modified. Usually, only the From, Date, Message-ID, and Subject fields are copied from the original message.
You can specify additional header fields to be copied from original postings to the messages sent to subscribers - directly or as parts of digests.
RFC822 Fields to Keep: Use these fields to specify the names of additional RFC822 header fields to be copied from the original postings to the distributed messages. If you want to remove a name, enter an empty string into the name field.
If you want to copy all header fields, enter the asterisk (*) symbol into the first field.
If you want to copy the Message-ID for the messages distributed using the "feed" mode, include the Message-ID field name.
If the To And Cc option is set to: