dkimproxy-sign(1) on Linux
The text c5489a1d91e7, as Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie), Debian 7 (Wheezy), Debian 6.0 (Squeeze), Debian 5.0 (Lenny) shipped it. The page shows this text now.
computes a DKIM signature for an email message