s-nail(1) on Linux
The text 7ece53e13824, as Debian 10 (Buster) shipped it.
send and receive Internet mail
Flags it lists
-
-# -
-. -
-: -
-A -
-B -
-D -
-E -
-F -
-H -
-L -
-M -
-N -
-R -
-S -
-V -
-X -
-a -
-b -
-c -
-d -
-e -
-f -
-h -
-i -
-m -
-n -
-q -
-r -
-s -
-t -
-u -
-v -
-~