You are looking at the HTML representation of the XML format.
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>
    <pageswithprop pwpcontinue="56" />
  </query-continue>
  <query>
    <pageswithprop>
      <page pageid="10" ns="14" title="Category:Objects" value="Objects" />
      <page pageid="33" ns="5000" title="Objects:Meta Object Definitions" value="Meta Object Definitions" />
      <page pageid="34" ns="5000" title="Objects:Meta Object Nature" value="Meta Object Nature" />
      <page pageid="38" ns="5000" title="Objects:BPMN 2.0 versus eXtended BPMN (X-BPMN)" value="BPMN 2.0 versus eXtended BPMN (X-BPMN)" />
      <page pageid="39" ns="5000" title="Objects:Organizational Role Notations" value="Organizational Role Notations" />
      <page pageid="40" ns="5000" title="Objects:Social Media Notations" value="Social Media Notations" />
      <page pageid="43" ns="5000" title="Objects:About Enterprise Ontology" value="About Enterprise Ontology" />
      <page pageid="50" ns="5000" title="Objects:About Enterprise Semantics" value="About Enterprise Semantics" />
      <page pageid="52" ns="5000" title="Objects:The Semantic Relationships of Meta Objects" value="The Semantic Relationships of Meta Objects" />
      <page pageid="55" ns="14" title="Category:Maps" value="Maps" />
    </pageswithprop>
  </query>
</api>