isotptun(1) on Linux
The text a179342cb9e9, as Debian 10 (Buster) shipped it.
manual page for isotptun 2018.02.0-1
Flags it lists
-
-D -
-L -
-P -
-b -
-d -
-h -
-m -
-n -
-p -
-s -
-v -
-w -
-x