This is documentation about a configuration directive, which can be placed within Movable Type’s core configuration file,
mt-config.cgi, to customize the behavior of the system.
When this value is set to an email address, MT will send all outgoing mail to this address instead of the usual recipient.
If you’re developing applications that use MT’s mailer (MT::Mail) then
you might find this option a useful alternative to the
MailTransfer debug option while debugging.