CityUHK Single Sign-On (OpenID Connect / OAuth 2.0)
CityUHK's OpenID Connect and OAuth 2.0 authorization server on the university's own hostname auth.cityu.edu.hk, which CNAMEs to cityu.customdomains.okta.com. Serves an OpenID Connect Discovery 1.0 document and an RFC 8414 authorization-server metadata document, both publicly readable, with issuer https://auth.cityu.edu.hk. The configuration is CityUHK's; the platform is Okta.