title: What is git diff origin master supposed to do?
body: <p>From a git branch, a colleague of mine ran </p>
  
  <pre><code>git diff origin master
  </code></pre>
  
  <p>What is it supposed supposed to do? What does <code>origin</code> separately point to? </p>
  
  <p>This is related, but not covered in 
  <a href="https://stackoverflow.com/questions/18137175/in-git-what-is-the-difference-between-origin-master-vs-origin-master">In Git, what is the difference between origin/master vs origin master?</a></p>