private static Stream<String> getDefaultAttributeMappings() {
        return Stream.of(
            CasWebflowConstants.ATTRIBUTE_WARN_ON_REDIRECT,
            CasWebflowConstants.ATTRIBUTE_PUBLIC_WORKSTATION,
            CasWebflowConstants.ATTRIBUTE_TARGET_TRANSITION,
            CasWebflowConstants.ATTRIBUTE_AUTHENTICATION_RESULT,
            CasWebflowConstants.ATTRIBUTE_AUTHENTICATION_RESULT_BUILDER,
            CasWebflowConstants.ATTRIBUTE_AUTHENTICATION,
            CasWebflowConstants.ATTRIBUTE_SERVICE,
            CasWebflowConstants.ATTRIBUTE_REGISTERED_SERVICE);
    }
The flow definition registry for the mfa flow.
core/cas-server-core-webflow-mfa-api/src/main/java/org/apereo/cas/web/flow/configurer/AbstractCasMultifactorWebflowConfigurer.java