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>
    <allmessages>
      <message name="ipb-blockingself" xml:space="preserve">你要封禁自己！確認要這樣做嗎？</message>
      <message name="ipb-blocklist" xml:space="preserve">檢視現有的封鎖</message>
      <message name="ipb-blocklist-contribs" xml:space="preserve">$1的貢獻</message>
      <message name="ipb-change-block" xml:space="preserve">利用這些設定重新封鎖用戶</message>
      <message name="ipb-confirm" xml:space="preserve">確認封禁</message>
      <message name="ipb-confirmhideuser" xml:space="preserve">你要封禁用戶並隱藏其用戶名，這會隱藏在所有列表及日誌中涉及此用戶之用戶名。你確定要這樣做嗎？</message>
      <message name="ipb-default-expiry" xml:space="preserve" />
      <message name="ipb-disableusertalk" xml:space="preserve">禁止被封禁用戶編輯自己的討論頁</message>
      <message name="ipb-edit-dropdown" xml:space="preserve">編輯封鎖原因</message>
      <message name="ipb-hardblock" xml:space="preserve">防止已登入用戶從該IP地址編輯</message>
      <message name="ipb-needreblock" xml:space="preserve">$1已經被封鎖。您是否想更改這個設定？</message>
      <message name="ipb-otherblocks-header" xml:space="preserve">其他{{PLURAL:$1|封鎖|封鎖}}</message>
      <message name="ipb-unblock" xml:space="preserve">解除禁封使用者名或IP地址</message>
      <message name="ipb-unblock-addr" xml:space="preserve">解除封鎖$1</message>
    </allmessages>
  </query>
</api>