Comment 13 for bug 328353

> is it correct to assume that they will only be archived and not resend again to members of the list, thus duplicated ?

Yes, the messages that were shunted during archiving will be unshunted to the archive queue and only archived, not resent to the list. You can verify this as follows. Do

 bin/dumpdb qfiles/shunt/xxx.pck

This will dump two objects - the message and the message metadata. The metadata will have an attribute 'whichq' which is the original queu to which the message will be unshunted. If this is 'archive', the unshunted message will only be archived. If it is 'out' the unshunted message will be sent to the 'recipients' in the metadata. If this is 'in', the unshunted message will be passed through those handlers remaining in 'pipeline'.