For the record, the <pubInfo> element is defined as such:

<xs:element name="pubInfo">

 <xs:annotation>

   <xs:documentation>

Publishing information filled when distributing the object to various destinations. The attribute is not meant to be edited directly, but filled by custom workflow when publishing.

   </xs:documentation>

 </xs:annotation>

 <xs:complexType>

   <xs:sequence>

     <xs:element name="item" minOccurs="0" maxOccurs="unbounded" gs:ordered="false">

     <xs:complexType>

       <xs:attribute name="name">

         <xs:annotation>

           <xs:documentation>Name of the parameter.</xs:documentation>

          </xs:annotation>

          <xs:simpleType>

            <xs:restriction base="xs:string">

              <xs:minLength value="1"/>

              <xs:maxLength value="30"/>

              <xs:pattern value="[A-Za-z0-9]+" />

            </xs:restriction>

          </xs:simpleType>

         </xs:attribute>

         <xs:attribute name="value" type="xs:string">

           <xs:annotation>

             <xs:documentation>Value of the parameter.</xs:documentation>

           </xs:annotation>

         </xs:attribute>

         <xs:attribute name="valueExtra" type="xs:string">

           <xs:annotation>

             <xs:documentation>Value of the extra parameter.</xs:documentation>

           </xs:annotation>

         </xs:attribute>

      </xs:complexType>

     </xs:element>

    </xs:sequence>

  </xs:complexType>

</xs:element>

It is defined in Tark4Include.xsd, in:

<xs:group name="archiveObjectExtra">

  ....

  <xs:sequence>

    ....

    <xs:element name="pubInfo">

     ....

    </xs:element>

  </xs:sequence>

</xs:group>