Value,Description,Reference
traceback,The incident was sent for trace-back purposes.,[RFC7970]
mitigation,"The incident was sent to request aid in
        mitigating the described activity.",[RFC7970]
reporting,"The incident was sent to comply with reporting
        requirements.",[RFC7970]
watch,"The incident was sent to convey indicators that should
        be monitored.",[RFC7970]
other,"The incident was sent for purposes specified in the
        Expectation class.",[RFC7970]
ext-value,"A value used to indicate that this attribute is
        extended and the actual value is provided using the
        corresponding ext-* attribute.  See Section 5.1.1 of [RFC7970].",[RFC7970]