   |
     /          v
a---b---c---d  branch 'master' (refers to commit 'd')
    ^
    |
  tag 'v2.0' (refers to commit 'b')</pre>
</div>
</div>
<div class="paragraph">
<p>It is important to realize that at this point nothing refers to commit
<code>f</code>. Eventually commit <code>f</code> (and by extension commit <code>e</code>) will be deleted
by the routine Git garbage collection process, unless we create a reference
before that happens. If we have not yet moved away from commit <code>f</code>,
any of t