Assignment from unset variable | What is _jQuery for?
<p>This value is set before jQuery has been exposed to the global scope:</p>

<pre><code>_jQuery = window.jQuery,
</code></pre>

<p>Near the end of the IIFE and after the above statement there is</p>

<pre><code>window.jQuery = window.$ = jQuery;
</code></pre>

<p>This is from the <a href="http://code.jquery.com/jquery-latest.js" rel="nofollow">jQuery development source</a>.</p>

<p>What compiler mechanism allows jQuery to do an assignment from an unset variable.</p>

<p>Also, what is _jQuery for in general?</p>
