title: Should full backup content xml file be empty or not added at all to include all?
body: <p>So I was adding some stuff to my application manifest and I saw that I had a warning on my application tag:</p>
  
  <blockquote>
    <p>On SDK version 23 and up, your app data will be automatically backed up and restored on app install. Consider adding the attribute android:fullBackupContent to specify an @xml resource which configures which files to backup.</p>
  </blockquote>
  
  <p>And then I searched up for that. Apparently there are only 2 tags for that: <code>&lt;include&gt;</code> and <code>&lt;exclude&gt;</code>. I don't want to exclude any files from the backup as I don't have any local-depending files, and I don't need any <code>&lt;include&gt;</code> tags as</p>
  
  <blockquote>
    <p><strong><code>&lt;include&gt;:</code></strong> Specifies a set of resources to back up, instead of having the system back up all data in your app by default.</p>
  </blockquote>
  
  <p>When I saw that if I don't put any <code>&lt;include&gt;</code> tags, then the system will <code>back up all data in your app by default</code>, which is exactly what I want.</p>
  
  <p>Now I have this question: should I add the <code>backup_content.xml</code> file, but empty as the default settings are good, or not add the file at all? (in which case Android Studio will complain)</p>