Type: boolean
Default: set
Controls whether or not the Mail-Followup-To header field is generated when sending mail. When set, Mutt will generate this field when you are replying to a known mailing lists.
The purpose of this field is to prevent you from receiving duplicate copies of replies to messages which you send by specifying that you will receive a copy of the message if it is addressed to the mailing list (and thus there is no need to also include your address in a group reply).