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HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allfileusages gafcontinue="BPM_Change_Management_Lifecycle.png|4084" />
  </query-continue>
  <query>
    <pages>
      <page pageid="348" ns="5009" title="Industry:Insurance" />
      <page pageid="2397" ns="5010" title="LEAD Reference Content:BPMN Model" />
      <page pageid="3875" ns="5010" title="LEAD Reference Content:Overview - BA Retap" />
      <page pageid="4083" ns="5010" title="LEAD Reference Content:SAP BPM Center of Excellence" />
      <page pageid="4084" ns="5010" title="LEAD Reference Content:SAP BPM Change Management Lifecycle" />
    </pages>
  </query>
</api>