Where and how is the _ViewStart.cshtml layout file linked?

Here’s the About.cshtml from the default MVC 3 template:

@{
    ViewBag.Title = "About Us";
}

<h2>About</h2>
<p>
     Put content here.
</p>

I would expect that a reference to the _ViewStart file would be found in the About.cshtml, but clearly it’s not.

I’ve looked in global.asax and web.config, but I can’t find out how the About.cshtml file is “linked” with the layout from the _ViewStart file.

Everything works as expected, I’d just like to know what’s going on under the hood…