telnetd(8) on Linux
The text 0adf711de39a, as Debian 4.0 (Etch), Debian 3.1 (Sarge) shipped it.
DARPA TELNET protocol server
Flags it lists
-
-B -
-D -
-L -
-S -
-U -
-X -
-a -
-h -
-k -
-l -
-n -
-r -
-u -
-y