title: custom branch storage in git
body: <p>Can I have branches stored in some custom place, such as <code>refs/custom_heads</code>? Will not garbage collection treat commits from that branches as garbage?</p>
  
  <p>Are there any convention of where branches should be placed, except <code>refs/heads</code>, <code>refs/remotes</code> and <code>refs/tags</code>?</p>