<p>Press I (Shift+i) to toggle hidden files in the NERDTree explorer window.</p>
<p>To enable this behavior by default, add this line to your <code>.vimrc</code> file:</p>
<pre><code class="lang-auto">let NERDTreeShowHidden=1
</code></pre>
<p>For more detail, access the NERDTree help file <code>:help NERD_tree.txt</code> and search for “hidden”.</p>