boxes(1) on Linux
The text 7c792efeb447, as Debian 9 (Stretch) shipped it.
text mode box and comment drawing filter
Flags it lists
-
-a -
-c -
-d -
-f -
-h -
-i -
-k -
-l -
-m -
-p -
-r -
-s -
-t -
-v