As implied by its name, the XML view displays an instance in XML format. If you save the XML text, you can load the instance later from the visualizer.
Here is a sample XML file:
<alloy>
<sig name="Name" extends="univ">
<atom name="Name$0"/>
<atom name="Name$1"/>
</sig>
<sig name="Date" extends="univ">
<atom name="Date$0"/>
</sig>
<sig name="BirthdayBook" extends="univ">
<atom name="BirthdayBook$0"/>
<atom name="BirthdayBook$1"/>
</sig>
<field name="known">
<type> <sig name="BirthdayBook"/> <sig name="Name"/> </type>
<tuple> <atom name="BirthdayBook$1"/> <atom name="Name$1"/> </tuple>
</field>
<field name="date">
<type> <sig name="BirthdayBook"/> <sig name="Name"/> <sig name="Date"/> </type>
<tuple> <atom name="BirthdayBook$1"/> <atom name="Name$1"/> <atom name="Date$0"/> </tuple>
</field>
</instance>
</alloy>