title: What does "Filtering content" mean when doing a git clone?
body: <p>I cloned a git repo and noticed a status line <code>Filtering content</code> which was very slow. This doesn't usually appear. What is it?</p>
  
  <pre><code>remote: Enumerating objects: 30, done.
  remote: Counting objects: 100% (30/30), done.
  remote: Compressing objects: 100% (26/26), done.
  remote: Total 16592 (delta 6), reused 9 (delta 4), pack-reused 16562
  Receiving objects: 100% (16592/16592), 14.14 MiB | 1.01 MiB/s, done.
  Resolving deltas: 100% (7529/7529), done.
  Checking out files: 100% (11475/11475), done.
  Filtering content:   6% (115/1729), 390.32 MiB | 1.12 MiB/s
  </code></pre>