title: What does the "r" mean in the "nl-rNL" locale?
body: <p>I have a Android app project, and one of the locale dirs has the suffix <code>nl-rNL</code> and I was wondering what that <code>r</code> stands for. I know almost for sure that this isn't a typo, because the resource is actually used in the app.</p>
  <p>I tried looking at the <a href="https://developer.android.com/guide/topics/resources/multilingual-support" rel="nofollow noreferrer">documentation</a>, but couldn't find it.</p>