mailbox(8) on Linux
The text 9f3cce8b8337, as Debian 2.1 (Slink), Debian 2.0 (Hamm) shipped it.
zmailer local delivery transport agent
Flags it lists
-
-8 -
-M -
-V -
-a -
-b -
-c -
-h -
-l -
-r