ReturnReceipt.br is an ARexx for use with THOR, and also relies on a
correctly configured SortMail trigger.

As you probably know, when you write messages in THOR there is an option in
the "Extra Message Options" window to ask for a receipt from the sender.
This effectively puts a "Return-Receipt-To: <address>" line in the header.
What happens if somebody sends you a message like this asking for a
receipt?  Nothing :-(  This is where my script comes in...

My script will automatically create a receipt message and add it as an
event. It will add "RECEIPT:" to the beginning of the subject, and put the
"To" address, message date, message id and the original subject in the
message.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                  250     468  53.4% -lh5- 5d5b Apr 28  1997 ReturnReceipt.guide.info
[generic]                 1608    3593  44.8% -lh5- ba0a Apr 20  1998 ReturnReceipt.br
[generic]                 3117    7087  44.0% -lh5- fe27 Apr 20  1998 ReturnReceipt.guide
[generic]                  481     868  55.4% -lh5- 3eb8 Apr 20  1998 ReturnReceipt.readme
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         4 files    5456   12016  45.4%            Apr 21  1998