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="Windows関連/MSYS2+VSCodeでC環境" />
  </query-continue>
  <query>
    <pages>
      <page pageid="9" ns="0" title="Linux関連" />
      <page pageid="13" ns="0" title="Linux関連/Asterisk(ひかり電話対応)の設定" />
      <page pageid="12" ns="0" title="Linux関連/DHCPサーバーの設定" />
      <page pageid="14" ns="0" title="Linux関連/WebDAVの設定" />
      <page pageid="15" ns="0" title="Linux関連/gitlabのセットアップ" />
      <page pageid="10" ns="0" title="Linux関連/sshdをtcpserver経由で動かす" />
      <page pageid="16" ns="0" title="Linux関連/tinydns(ndjbdns)を使う" />
      <page pageid="11" ns="0" title="Linux関連/tinydnsを使う" />
      <page pageid="4" ns="0" title="Sandbox" />
      <page pageid="17" ns="0" title="Windows関連" />
    </pages>
  </query>
</api>