title: What is the `file` URI scheme in Puppet?
body: <p><a href="https://docs.puppetlabs.com/references/latest/type.html#file-attribute-source" rel="nofollow">The documentation for the <code>source</code> attribute for the <code>file</code> resource type</a> says:</p>
  
  <blockquote>
    <p>The available URI schemes are <code>puppet</code> and <code>file</code>. <code>puppet</code> URIs will ...</p>
  </blockquote>
  
  <p>It then explains the <code>puppet</code> URI scheme, but doesn't say anything about the <code>file</code> URI scheme. What is it? What does it mean to assign <code>"file://foo/bar/baz"</code> to the <code>source</code> attribute on a <code>file</code> resource?</p>