mail.mboxfile(8) on OpenBSD
The text c8f29ba6f552, as OpenBSD 7.9, OpenBSD 7.8, OpenBSD 7.7, OpenBSD 7.6, OpenBSD 7.5, OpenBSD 7.4, OpenBSD 7.3, OpenBSD 7.2, OpenBSD 7.1, OpenBSD 7.0, OpenBSD 6.9, OpenBSD 6.8, OpenBSD 6.7, OpenBSD 6.6, OpenBSD 6.5, OpenBSD 6.4 shipped it.
deliver mail to a file in mbox format