com/android/support/recommendation/maven-metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<metadata>
  <groupId>com.android.support</groupId>
  <artifactId>recommendation</artifactId>
  <versioning>
    <release>25.4.0</release>
    <versions>
      <version>26.0.0-beta1</version>
      <version>25.4.0</version>
    </versions>
    <lastUpdated>20170605183328</lastUpdated>
  </versioning>
</metadata>