A Bcc header *can* be included in the version of the message going to
the bcc'd user. *Some* MUAs split the message into multiple versions:
the ones going to the To's/Cc's do not have the Bcc: header, and the
ones going to each of the Bcc's have just that user listed. Other MUAs
choose a simpler method of just stripping Bcc: entirely and sending the
same version to all users.
Robert A. Rosenberg wrote:
Thank you for your reply. I read RFC5230 after I had sent my query so I
had seen that info. OTOH, I think the RFC in allowing bcc and/or
resent-bcc headers to be considered is in error since these headers
should never occur in the transmitted text of the message (the bcc is
stripped when the message is originally injected so it is not there and
thus I do not know if a resent-bcc can be created) unless something is
broken (such as the Apparently-To header injection bug that occurred in
the absence of any To/Cc addresses).