telnetd(8) on Linux
The text 3ff83468b0de, as Debian 10 (Buster) shipped it.
DARPA TELNET protocol server
Flags it lists
-
--authmode -
--debug -
--disable-auth-type -
--exec-login -
--linemode -
--no-hostinfo -
--no-keepalive -
--reverse-lookup -
--server-principal -
--usage -
--version -
-D -
-E -
-S -
-U -
-V -
-X -
-a -
-h -
-l -
-n