title: What is the purpose of *.ngsummary.json
body: <p>I've just learning about <code>AOT</code>, <code>ngc</code> etc. After running <code>ngc</code> I see plenty of <code>*.ngsummary.json</code> (in <code>src</code> folder, next to <code>*.ts</code> files). </p>
  
  <p>What are they for?</p>