I saw this parameter with the s_client command and it looks like:
$ openssl s_client -connect www.google.com:443 2>&1
When I ran the command without the 2>&1, the response didn't seem to be any different. I tried looking through documentation, but couldn't find anything. I don't even know what I'm supposed to be looking for.
P.S. This tweet is where I originally found the parameter.
