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>
    <alllinks galcontinue="User_Tools_Page" />
  </query-continue>
  <query>
    <pages>
      <page ns="0" title="Diag tools examples" missing="" />
      <page pageid="10" ns="0" title="Basic Commands" />
      <page pageid="2" ns="0" title="Inside an OFED distribution" />
      <page pageid="11" ns="0" title="Learning Infiniband" />
      <page pageid="4" ns="0" title="OSM ErrorMsg" />
      <page pageid="5" ns="0" title="OSM PML" />
      <page pageid="6" ns="0" title="OSM PerfManager" />
      <page pageid="7" ns="0" title="OpenStack" />
      <page pageid="9" ns="0" title="Overview of Error Counters" />
      <page pageid="8" ns="0" title="Partitions" />
    </pages>
  </query>
</api>