I used Thunderbird to move e-mails from one account into my Gmail account, but somehow some of the e-mails' From headers have disappeared. I would like to edit the e-mails to add these headers again.
Is there anyway I can froward all emails from a Gmail account to a number of other e-mail accounts and then setting the reply-to (or from) header as the Gmail's account? So multiple people can use ...
Is there any way to modify the mail headers in an outgoing message sent using Gmail? I'm interested in doing this to add an "Approved:" header to a Mailman announcements-only list (reference).