+These options do not normally need to be set, but can be useful in
+certian setups.
+
+* `openid_realm` can be used to control the scope of the openid request.
+ It defaults to the `cgiurl` (or `openid_cgiurl` if set); only allowing
+ ikiwiki's [[CGI]] to authenticate. If you have multiple ikiwiki instances,
+ or other things using openid on the same site, you may choose to put them
+ all in the same realm to improve the user's openid experience. It is an
+ url pattern, so can be set to eg "http://*.example.com/"
+
+* `openid_cgiurl` can be used to cause a different than usual `cgiurl`
+ to be used when doing openid authentication. The `openid_cgiurl` must
+ point to an ikiwiki [[CGI]], and it will need to match the `openid_realm`
+ to work.