10.12.22, 13:44 +0100, Wietse Venema:
https://www.postfix.org/postconf.5.html#sender_bcc_maps saysOptional BCC (blind carbon-copy) address lookup tables, indexed by sender address.but it doesn't specify whether "address" means envelope address, header address or both. OTOHPostfix routing is envelope based. Therefore, unless stated otherwise, "address" means "envelope".
Thanks for the clarification, Wietse! I'll keep that in mind. -- Regards mks