xbiff(1x) on Linux
The text 2df428cc7fd4, as Debian 3.0 (Woody) shipped it.
mailbox flag for X
Flags it lists
-
-bd -
-bg -
-bw -
-display -
-fg -
-file -
-geometry -
-help -
-rv -
-shape -
-update -
-volume -
-xrm