[keycloak-user] Not before policy in accesstoken uses dash-separator (in json), why?

Hello Keycloak gurus, Quick simple question out of curiosity. Since all other AccessToken fields use a underscore_separator, why is the not-before-policy with dashes. See: https://github.com/keycloak/keycloak/blob/3.1.x/core/src/main/java/org/ke... Anyone have a clue? Regards Jakob