title: Is it utf-8 suitable for text/plain mime type?
body: <p>I am exporting data through files. The output is base64 encoded data.</p>
  
  <pre><code>$data = base64_encode(serialize($data));
  </code></pre>
  
  <p>Which results in something like:</p>
  
  <pre><code>bGFzcyI6MTp7czo1OiJzZXR1cCI7YTo3Mzp7czoyNToicGFnZXNfY29udGFjdF91c19oZWFkbGlu
  </code></pre>
  
  <p>So I am wondering what charset is more suitable for this data (plain text). us-ascii seems enough but utf-8 always seems an error-proof default.</p>
  
  <pre><code>header('content-type: text/plain; charset=utf-8');
  </code></pre>