How to determine ACS URL

[Peter Schober]

* Mark Neidig <mneidig at ftni.com> [2015-02-03 17:49]:
> I'm told my company is a current Shibboleth user. I am replacing the
> developer that initially set up our Shibboleth. Our SSO code is in
> place and functional. I just need to add another client and I am
> having trouble determining the next step. I'm being asked for our
> ACS URL.

See also Scott's reply to Josh Christensen <jchristensen at ftni.com> on
a simliar same topic, a thread with the (non-sensical) subject:
"RE: users Digest, Vol 33, Issue 42", from March 2014.
-peter