http://www.rfc-editor.org/rfc/rfc3894.txt
RFC 3894: Sieve Extension: Copying Without Side Effects, J. Degener2004-10-01T23:00:00-00:00 This document defines a new keyword parameter, ":copy", to be used with the Sieve "fileinto" and "redirect" actions. Adding ":copy" to an action suppresses cancellation of the default "inbox" save. It allows users to add commands to an existing script without changing the meaning of the rest of the script. [STANDARDS-TRACK]