title: Firebase hosting rewrite rules based on language of browser
body: <p>I have a Firebase hosted website that contains an <code>index_fr.html</code> and <code>index_nl.html</code>.
  How can I create a rewrite rules that uses the user agent language to serve the correct <code>index_nl</code> or <code>index_fr</code> page (without using Firebase functions)?</p>