PennKey Identity Provider — SAML 2.0 / Shibboleth Metadata
Penn's Shibboleth identity provider publishes a signed SAML 2.0 EntityDescriptor at a well-known location (HTTP 200, application/xml, entityID https://idp.pennkey.upenn.edu/idp/shibboleth), carrying the Shibboleth metadata extension namespace and an embedded X.509 signing certificate. The same entity resolves live through InCommon MDQ as application/samlmetadata+xml, which makes federation membership verifiable rather than self-asserted. This is machine-readable infrastructure the institution itself operates, and it is the strongest institution-owned surface in this profile.