A file with extension .xref gets created and appears in the Applications window. All .xref files are based on the schema definition (XSD) file shown in the following example:

<?xml version="1.0" encoding="UTF-8" ?>
<schema xmlns="http://www.w3.org/2001/XMLSchema" 
        targetNamespace="http://xmlns.oracle.com/xref"
        xmlns:tns="http://xmlns.oracle.com/xref" elementFormDefault="qualified">
  <element name="xref" type="tns:xrefType"/>
  <complexType name="xrefType">
    <sequence>
      <element name="table">
        <complexType>
          <sequence>
            <element name="description" type="string" minOccurs="0"
                     maxOccurs="1"/>
            <element name="columns" type="tns:columnsType" minOccurs="0"
                     maxOccurs="1"/>
            <element name="rows" type="tns:rowsType" maxOccurs="1"
                     minOccurs="0"/>
          </sequence>
          <attribute name="name" type="string" use="required"/>
        </complexType>
      </element>
    </sequence>
  </complexType>
  
  <complexType name="columnsType">
    <sequence>
      <element name="column" minOccurs="1" maxOccurs="unbounded">
        <complexType>
          <attribute name="name" type="string" use="required"/>
        </complexType>
      </element>
    </sequence>
  </complexType>
  
  <complexType name="rowsType">
    <sequence>
      <element name="row" minOccurs="1" maxOccurs="unbounded">
        <complexType>
          <sequence>
            <element name="cell" minOccurs="1" maxOccurs="unbounded">
              <complexType>
                <attribute name="colName" type="string" use="required"/>
              </complexType>
            </element>
          </sequence>
        </complexType>
      </element>
    </sequence>
  </complexType>
</schema>