title: GitHub source dynamic navigation
body: <p>I was browsing thought GitHub today and noticed that the individual repository navigation doesn't use hash-bangs in the URL /#! or /# and the back button still works.  How do you think they are accomplishing this?  How does this affect search engine crawling from Googlebot?  I know it looks for # in the url.</p>
  
  <p>I'm really quite curious as I know using /# is quite debatable.</p>
  
  <p>Here's an example: <a href="https://github.com/mirah/pindah" rel="noreferrer">https://github.com/mirah/pindah</a></p>
  
  <p>Thanks!</p>