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 alcontinue="Windows関連/MSYS2+VSCodeでC環境" />
  </query-continue>
  <query>
    <alllinks>
      <l ns="0" title="Linux関連" />
      <l ns="0" title="Linux関連/Asterisk(ひかり電話対応)の設定" />
      <l ns="0" title="Linux関連/DHCPサーバーの設定" />
      <l ns="0" title="Linux関連/WebDAVの設定" />
      <l ns="0" title="Linux関連/gitlabのセットアップ" />
      <l ns="0" title="Linux関連/sshdをtcpserver経由で動かす" />
      <l ns="0" title="Linux関連/tinydns(ndjbdns)を使う" />
      <l ns="0" title="Linux関連/tinydnsを使う" />
      <l ns="0" title="Sandbox" />
      <l ns="0" title="Windows関連" />
    </alllinks>
  </query>
</api>