As 

This attribute is used to express the fact that the
associated element is either en envelope or an item. If omitted, the element is
considered an item (default behaviour). *An item contains the information
directly in itself. *An envelope would group items of the same nature, but the
informaton would in fact be in the child items.

Attribute Information

Used By

Attribute Group StatusGroup

Source 

<xs:attribute name="As" type="AsCodeType" use="optional">
  <xs:annotation>
    <xs:documentation xml:lang="EN">This attribute is used to express the fact that the associated element is either en envelope or an item. If omitted, the element is considered an item (default behaviour). *An item contains the information directly in itself. *An envelope would group items of the same nature, but the informaton would in fact be in the child items.</xs:documentation>
  </xs:annotation>
</xs:attribute>

Sample