/var/www/html/sp-metadata.xml
The entityId attribute specifies who we are:
<md:EntityDescriptor xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" entityID="https://shrine-sso-node01.catalyst.harvard.edu">
<md:SPSSODescriptor AuthnRequestsSigned="true" WantAssertionsSigned="true" protocolSupportEnumeration="urn:oasis:names:tc:SAML:2.0:protocol">
The <ds:X509Certificate> element contains the public key that was generated earlier:
<md:KeyDescriptor>
<ds:KeyInfo>
<ds:X509Data>
<ds:X509Certificate>MIIC6zCCAdOgAwIBAgIJAOy0nki3WAOVMA0GCSqGSIb3DQEBBQUAMBcxFTATBgNV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 </ds:X509Certificate>
</ds:X509Data>
</ds:KeyInfo>
</md:KeyDescriptor>
the "Location" xml attribute specifies the URL at which the IdP will post the user info after a successful login:
<md:AssertionConsumerService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" Location="https://shrine-sso-node01.catalyst.harvard.edu/Shibboleth.sso/SAML2/POST" index="1"/>
</md:SPSSODescriptor>
</md:EntityDescriptor>