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>
    <allpages apcontinue="CPUの詳細を調べる" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="2106" ns="0" title="B&#039;z" />
      <p pageid="2134" ns="0" title="BABYMETAL" />
      <p pageid="1823" ns="0" title="BLUE ENCOUNT" />
      <p pageid="841" ns="0" title="BTB溶液" />
      <p pageid="1890" ns="0" title="BUMP OF CHICKEN" />
      <p pageid="1489" ns="0" title="Base Ball Bear" />
      <p pageid="299" ns="0" title="BetterDeleteRevision" />
      <p pageid="1506" ns="0" title="Billboard JAPAN" />
      <p pageid="1537" ns="0" title="Billboard Japan Hot 100" />
      <p pageid="2850" ns="0" title="Bitnami版Redmineにプラグインを追加する" />
    </allpages>
  </query>
</api>