Value,Description,Reference
bytes,The element content is of type HEXBIN.,[RFC7970]
integer,The element content is of type INTEGER.,[RFC7970]
real,The element content is of type REAL.,[RFC7970]
string,The element content is of type STRING.,[RFC7970]
xml,The element content is XML.  See Section 5.2 of [RFC7970].,[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]