<xs:element name="feed">
    <xs:annotation>
        <xs:documentation>
        Describes the "schema" for a an XML feed to "googlebase".
        Note that this is only an "abstract schema" in the sense that
        google base does not currently accept a "feed" in this format.
        Instead, google base accepts feeds in a wide variety of "standard" XML 
        content feed formats (RSS2.0, Atom). The "item/entry" subelement of 
        a "RSS/Atom" feed corresponds to the "item" element defined below. 
        The sub elements of an item defined herein serve as the concrete
        definition of the "googlebase defined extensions" to the Atom/RSS
        schemas.
      </xs:documentation>
    </xs:annotation>
    <xs:complexType>
        <xs:sequence>
            <!-- All elements defined herein (besides item) are provided at feed registration. -->
            <xs:element name="item_type" type="xs:string" />
            <xs:element name="language" type="xs:string" minOccurs="0" />
            <xs:element ref="gn:item" maxOccurs="unbounded" />
        </xs:sequence>
    </xs:complexType>
</xs:element>