title: Merged Manifest Warning after upgrading Android Studio to 3.2.1
body: <p>After upgrading to <code>Android Studio 3.2.1</code>, when editing the <code>AndroidManifest.xml</code> file, I see my <code>&lt;application&gt;</code> section of the file highlighted in yellow (presumably due to warning below).
  I also see a new tab titled <code>Merged Manifest</code> which contains the warning :</p>
  
  <blockquote>
    <p>Merging Errors: Warning activity#com.google.firebase.auth.internal.FederatedSignInActivity@android:launch Mode was tagged at AndroidManifest.xml:24 to replace other declarations but no other declaration present app main manifest (this file), line 23</p>
  </blockquote>
  
  <p>Questions:  </p>
  
  <ol>
  <li><p>Is this new tab something new in AS 3.2.1?  Or is it showing up since AS 3.2.1 is finding a new warning that the previous version did not?</p></li>
  <li><p>What is the warning about?  Do I need to add an activity in my app's AndroidManifest.xml for Firebase for some reason?</p></li>
  <li><p>How do I fix it?</p></li>
  </ol>
  
  <p>(Note: there was probably a Firebase update as well around the same time.)</p>
  
  <p>Firebase is up-to-date at present.</p>
  
  <pre><code>implementation 'com.google.firebase:firebase-auth:16.0.5'
  implementation 'com.google.firebase:firebase-core:16.0.4'
  implementation 'com.google.firebase:firebase-crash:16.2.1'
  </code></pre>
  
  <p>Everything compiles and runs fine in spite of this.</p>