Some .aar files (e.g. support v4) contain an annotations.zip, which appears to be used by android lint.

E.g.: support-v4-23.4.0.aar contains /annotations.zip.

annotations.zip contains:
./android/support/v4/app/annotations.xml
./android/support/v4/media/annotations.xml
./android/support/v4/media/session/annotations.xml
./android/support/v4/view/annotations.xml
./android/support/v4/widget/annotations.xml

./android/support/v4/app/annotations.xml contains:
<?xml version="1.0" encoding="UTF-8"?>
<root>
  <item name="android.support.v4.app.DialogFragment void setStyle(int, int) 0">
    <annotation name="android.support.annotation.IntDef">
      <val name="value" val="{android.support.v4.app.DialogFragment.STYLE_NORMAL, android.support.v4.app.DialogFragment.STYLE_NO_TITLE, android.support.v4.app.DialogFragment.STYLE_NO_FRAME, android.support.v4.app.DialogFragment.STYLE_NO_INPUT}" />
    </annotation>
  </item>
  <item name="android.support.v4.app.FragmentTransaction android.support.v4.app.FragmentTransaction setTransition(int) 0">
    <annotation name="android.support.annotation.IntDef">
      <val name="value" val="{android.support.v4.app.FragmentTransaction.TRANSIT_NONE, android.support.v4.app.FragmentTransaction.TRANSIT_FRAGMENT_OPEN, android.support.v4.app.FragmentTransaction.TRANSIT_FRAGMENT_CLOSE}" />
    </annotation>
  </item>
</root>