Can't validate html wagn content+example

try this: http://validator.w3.org/check?uri=http%3A%2F%2Fwagn.org%2Ffeature_reference&charset=%28detect+automatically%29&doctype=Inline&group=0&user-agent=W3C_Validator%2F1.3+http%3A%2F%2Fvalidator.w3.org%2Fservices