The AttributeType has value Link if a model element has a link to another model element. In this case there are no TypeProperty DataType = xxx XML child elements.
Example: QPR Modeling Client exports a process step's owner (i.e. a process step has a link to a resource) as a link.
<ModelAttributeType Name="Owner" AttributeType="Link">
<FieldType Name="ElementName" DataType="string" />
<FieldType Name="ElementId" DataType="string" />
<FieldType Name="TypeName" DataType="string" />
<FieldType Name="TypeID" DataType="string" />
</ModelAttributeType>
<Attribute AttributeName="Owner">
<Record>
<Field Name="ElementName" Value="KJu" />
<Field Name="ElementId" Value="PG_RE26" />
<Field Name="TypeName" Value="Resource type" />
<Field Name="TypeID" Value="PG_RE16" />
</Record>
</Attribute>
