An OpenID configuration endpoint publishes an identity provider’s OpenID Connect metadata, including the service endpoints a client needs for authorization and token issuance. Clients retrieve it before starting an authorization code flow, rather than hard-coding those URLs. section 12.3
Discovering the provider endpoints
For an identity provider running on localhost:9000, request http://localhost:9000/.well-known/openid-configuration. The response identifies the authorization endpoint at /oauth2/authorize and the token endpoint at /oauth2/token. The client can then use those discovered URLs to obtain an authorization code and exchange it for tokens. section 12.3
