(optional) If specified, appends this text to the end of every nightly digest and index message from this list.
By default, when you create a mailing list, this footer is added:
---This footer uses the mail merge fields to allow failsafe unsubscribing. See How can I use the Mail merge feature?.
You are currently subscribed to $subst('List.Name') as: $subst('Recip.EmailAddr')
To unsubscribe send a blank email to $subst('Email.UnSub')
Of course, you can change this footer to be anything you like, or remove it completely.