http://spaces.internet2.edu/Shibboleth.sso/Metadata spaces.internet2.edu.crt
https://kalmar2.org/simplesaml/module.php/aggregator/?id=kalmarcentral2&set=saml2&exclude=sweden&mimetype=application/xml kalmar-signer.crt
http://discovery.shibboleth.net/shibboleth.net-metadata.xml