title: What are .git/info/grafts for?
body: <p>I am trying to figure out what is the 'grafts' in the Git.</p>
  
  <p>For example, in one of the latest comments <a href="http://web.archive.org/web/20080930112610/http://log.emmanuelebassi.net/archives/2007/09/when-the-levee-breaks/" rel="noreferrer">here</a>, Tobu suppose to use <b>git-filter-branch</b> and <b>.git/info/grafts</b> to join two repositories.</p>
  
  <p>But I don't understand why I need these <em>grafts</em>? It seems, that all work without last two commands.</p>