TU Berlin Matrix Homeserver (Client-Server API)
TU Berlin runs its own Matrix homeserver for institutional messaging, with an Element web client at chat.tu-berlin.de and documentation at docs.chat.tu-berlin.de. The Client-Server API answers unauthenticated where the specification says it should: /_matrix/client/versions returns 200 advertising r0.0.1 through v1.12, /_matrix/federation/v1/version reports Synapse 1.157.2, /.well-known/matrix/client returns the homeserver base URL and a Jitsi domain at meet.innocampus.tu-berlin.de, and /_matrix/client/v3/login lists m.login.password and m.login.application_service. Guest access is disabled. A genuine campus-life API surface, institution-operated, speaking an open standard.