https://blog.wongcw.com/2019/12/04/firefox-private-network%e7%8f%be%e6%93%b4%e5%a4%a7beta%e6%b8%ac%e8%a9%a6%e7%af%84%e5%9c%8d%e5%a2%9e%e5%bc%b7%e7%94%a8%e6%88%b6%e9%9a%b1%e7%a7%81%e4%bf%9d%e8%ad%b7/