Let us take an example. A message body was in Q-P on the wire. Is the IMAP
implementation entitled to store it in only its decoded (8bit) form? Suppose
the message was in fact signed by DKIM or PGP-mime (both of which are
supposed to sign the Q-P form - a bad design decision, but there it is). The
recipient (or his MUA) finds that the signature is broken. So the recipient
requests to see the original form of the message so that he can check for
himself exactly why the signature did not work (maybe some trailing empty
line had got lost, and by manually restoring it he can make the signature
work).
