title: What source comments does Xcode recognize as tags?
body: <p>This is mostly for curiosity's sake. I've known for awhile that Xcode is capable of recognizing comments in the form of <code>// TODO: Something I don't feel like doing now</code>. Adding that line to the source of a file will cause that TODO comment to show up in Xcode's navigation bar:</p>
  
  <p><img src="https://i.stack.imgur.com/GMi4H.png" alt="enter image description here">  </p>
  
  <p>I also recently discovered that comments of the form <code>// MARK: Something</code> can achieve the same effect as <code>#pragma mark</code>ing something. So I can write a comment that looks like:</p>
  
  <pre><code>// MARK: -
  // MARK: Future Improvements:
  // TODO: Make something better
  // TODO: Fix some bug
  </code></pre>
  
  <p>And Xcode will render it out like this:  </p>
  
  <p><img src="https://i.stack.imgur.com/eNuhP.png" alt="enter image description here">  </p>
  
  <p>Which leads me to wonder: Are there other kinds of comments that Xcode can understand to improve project navigation?</p>