Bouncing

The message-bounce command will, if the current buffer contains a bounced mail message, pop up a message buffer stripped of the bounce information. A bounced message is typically a mail you’ve sent out that has been returned by some mailer-daemon as undeliverable.

Headers that match the message-ignored-bounced-headers regexp will be removed before popping up the buffer. The default is ‘^\\(Received\\|Return-Path\\|Delivered-To\\):’.