virtual_mailbox_maps - just for virtual(8) ?

[Phil Howard]

Is virtual_mailbox_maps just for virtual(8) (the postfix virtual
delivery agent ... which I am not using) ... or is it also used for
smtpd_reject_unlisted_recipient even when virtual_transport =
something else like dovecot?  Can it just have an "OK" value to mean
"yeah, this is a real recipient here, go ahead and accept the mail and
just deliver it to the same place" or do I need to put delivery paths
in there?