title: How filter JSON files with Intent.ACTION_OPEN_DOCUMENT?
body: <p>When I try to open a <code>.json</code> file with</p>
  
  <pre><code>startActivityForResult(Intent(Intent.ACTION_OPEN_DOCUMENT).apply {
      addCategory(Intent.CATEGORY_OPENABLE)
      type = "application/json"
  }, 0)
  </code></pre>
  
  <p>the chooser lists files of <em>all</em> types instead of just <code>.json</code> files. And what's worth, all files are greyed out, I can't select any, <strong>not even</strong> my <code>.json</code> files.</p>
  
  <p>However, when I change <code>application/json</code> to <code>*/*</code>, the files aren't greyed out and I can open them.</p>
  
  <p>With <code>ACTION_GET_CONTENT</code> instead of <code>ACTION_OPEN_DOCUMENT</code> the behaviour is the same.</p>
  
  <p>Why doesn't the type setting work as expected? How to make it work?</p>