2.1.2 [W3C-XSS] Section 3.3.4, Element Declaration Validation Rules


The specification states:

 4 If there is an attribute information item among the element information item's 
 [attributes] whose [namespace name] is identical to 
 http://www.w3.org/2001/XMLSchema-instance and whose [local name] is type ...
 4.2 The ·local name· and ·namespace name· (as defined in QName Interpretation 
 (§3.15.3)), of the ·actual value· of that attribute information item must resolve 
 to a type definition, as defined in QName resolution (Instance) (§3.15.4) – 
 [Definition:]  call this type definition the local type definition;


An attribute information item that does not resolve to a valid type does not cause an error.