grotty(1) on Linux
The text c9fc31e1ab4e, as Debian 9 (Stretch) shipped it.
groff driver for typewriter-like devices
Flags it lists
-
-B -
-F -
-U -
-b -
-c -
-d -
-f -
-h -
-i -
-o -
-r -
-u -
-v