title: Refer properties in serverless yaml
body: <p>In documentation </p>
  
  <blockquote>
    <p><a href="https://serverless.com/framework/docs/providers/aws/guide/serverless.yml/" rel="nofollow noreferrer">https://serverless.com/framework/docs/providers/aws/guide/serverless.yml/</a></p>
  </blockquote>
  
  <p>I find there are a couple of places where certain properties or variables are referred to as something like <code>$.stageVariables</code>,<code>$.time</code>,<code>$.userIdentity.type</code>, etc. It is kind of confusing to me about their meanings. Is there any documentation somewhere around this kind of variables? I only find the variable related documentation here </p>
  
  <blockquote>
    <p><a href="https://serverless.com/framework/docs/providers/aws/guide/variables/#referencing-serverless-core-variables" rel="nofollow noreferrer">https://serverless.com/framework/docs/providers/aws/guide/variables/#referencing-serverless-core-variables</a></p>
  </blockquote>
  
  <p>which didn't cover anything on this.</p>
  
  <p>Thanks!</p>