opendkim(8) on Linux
The text d7526a84b10f, as Debian 7 (Wheezy) shipped it.
DKIM signing and verifying filter for MTAs
Flags it lists
-
-A -
-D -
-F -
-L -
-P -
-Q -
-S -
-T -
-V -
-W -
-b -
-c -
-d -
-e -
-f -
-k -
-l -
-n -
-o -
-p -
-q -
-r -
-s -
-t -
-u -
-v -
-x