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>
    <allimages gaicontinue="1.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="2355" ns="6" title="File:-Chart-01-SouthChinaSea Figures-.png" />
      <page pageid="2348" ns="6" title="File:-MAP-01 SouthChinaSea MaritimeTerritory-.jpg" />
      <page pageid="2346" ns="6" title="File:-MAP-02 SouthChinaSea Nine dash line claim-.jpg" />
      <page pageid="2349" ns="6" title="File:-MAP-03 SouthChinaSea Nine dash line historical map-.gif" />
      <page pageid="2347" ns="6" title="File:-MAP-04 SouthChinaSea Islands in dispute-.jpg" />
      <page pageid="2350" ns="6" title="File:-MAP-05 SouthChinaSea Crude oil trade flow-.jpg" />
      <page pageid="2351" ns="6" title="File:-MAP-06 SouthChinaSea Oil and Natural Gas Platform-.jpg" />
      <page pageid="2352" ns="6" title="File:-MAP-07 SouthChinaSea ChinavsPhilippines-.jpg" />
      <page pageid="2353" ns="6" title="File:-MAP-08 SouthChinaSea ChinavsVietnam-.jpg" />
      <page pageid="2354" ns="6" title="File:-Timeline01 SouthChinaSea ChinavsPhilippines-.jpg" />
    </pages>
  </query>
</api>