https://www.keycloak.org/docs/latest/server_admin/index.html#ref-personal-data-collected_server_administration_guide
That‘s the only thing which exists.
As Keycloak is not a hosted/managed service, there‘s no need to provide a privacy policy. This task is up to you (if you operate Keycloak), to explain how you use the data which is collected and processed by Keycloak. As you run Keycloak, you have full access and control over the data and thus you are responsible for that.