title: Listing and deleting Git commits that are under no branch (dangling?)
body: <p>I've got a Git repository with plenty of commits that are under no particular branch, I can <code>git show</code> them, but when I try to list branches that contain them, it reports back nothing.</p>
  
  <p>I thought this is the dangling commits/tree issue (as a result of -D branch), so I pruned the repo, but I still see the same behavior after that:</p>
  
  <pre><code>$ git fetch origin
  
  $ git fsck --unreachable
  $ git fsck
  </code></pre>
  
  <p>No output, nothing dangling (right?). But the commit exists</p>
  
  <pre><code>$ git show 793db7f272ba4bbdd1e32f14410a52a412667042
  commit 793db7f272ba4bbdd1e32f14410a52a412667042
  Author: ...
  </code></pre>
  
  <p>and it is not reachable through any branch as</p>
  
  <pre><code>$ git branch --contains 793db7f272ba4bbdd1e32f14410a52a412667042
  </code></pre>
  
  <p>gives no output.</p>
  
  <p>What exactly is the state of that commit? How can I list all commits in a similar state? How can I delete commits like those?</p>