title: What workbox strategy is used for precached assets when using workbox-webpack-plugin?
body: <p>I'm trying to understand workbox and service-workers.</p>
  
  <p>What is the workbox strategy used for precached assets when using the workbox-webpack-plugin and GenerateSW mode? ie. cacheFirst, staleWhileRevalidate, etc. Because it seems that I do not have set up a route/strategy for precached assets in order for the service-worker to update the caches for these assets. So what is the default handler for these?</p>
  
  <p>And secondly, how do the Cache-Control headers from the server response play a role in the workbox strategy to refresh the assets? If at all.</p>
  
  <p>Answering the question wrt the root /index.html asset would be most helpful to me.</p>
  
  <p>Thanks.</p>