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>
    <alltransclusions gatcontinue="For|136" />
  </query-continue>
  <query>
    <pages>
      <page pageid="123" ns="0" title="API AbbrLocationStr" />
      <page pageid="124" ns="0" title="API AbortMission" />
      <page pageid="127" ns="0" title="API Article" />
      <page pageid="128" ns="0" title="API CanUseAddon" />
      <page pageid="129" ns="0" title="API CanUseMerchandise" />
      <page pageid="130" ns="0" title="API CancelPurchaseShipLoadout" />
      <page pageid="132" ns="0" title="API CheckCharProximity" />
      <page pageid="133" ns="0" title="API CheckProximityWarning" />
      <page pageid="134" ns="0" title="API CheckStorageAndUnloadCargo" />
      <page pageid="135" ns="0" title="API ClearGeneralChatLog" />
    </pages>
  </query>
</api>