xs:openAttrs 

This type is extended by almost all schema types
to allow attributes from other namespaces to be
added to user schemas.

Complex Type Information

Model

Attributes

Used By

Complex Type xs:annotated
Elements xs:annotation, xs:override, xs:redefine, xs:schema

Source 

<xs:complexType name="openAttrs">
  <xs:annotation>
    <xs:documentation>This type is extended by almost all schema types to allow attributes from other namespaces to be added to user schemas.</xs:documentation>
  </xs:annotation>
  <xs:complexContent>
    <xs:restriction base="xs:anyType">
      <xs:anyAttribute namespace="##other" processContents="lax"/>
    </xs:restriction>
  </xs:complexContent>
</xs:complexType>