title: What is the default action when I don't set http_cache in view config in Pyramid framework
body: <p>Regarding the document of <a href="http://docs.pylonsproject.org/docs/pyramid/en/latest/narr/viewconfig.html" rel="nofollow">Pyramid framework</a>, they description how to user http_cache parameter.</p>
  
  <p>However, this document doesn't explain the default action if user doesn't set this parameter.
  The default action mean browser will cache the response or not cache the response or base on the behavior for each browser</p>
  
  <p>So, could you please share this case to me?</p>
  
  <p>Thank you.</p>