Why Remove and Add ExtensionlessUrlHandler?

I was starting a new ASP.NET MVC 5 project today, and like always was copy/pasting some code from a previous project. No need to reinvent anything if the work has been done... right?

In the web.config I saw the following under <system.webServer><handlers>

<system.webServer>
    <handlers>
        ...
        <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
        <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
        ...
    </handlers>
</system.webServer>

Why would that even be there? Removing and adding again... There must be a point to this, right?

The default ExtensionlessUrlHandler-Integrated-4.0 handler only registers with a small set of verbs: GET, HEAD, POST, DEBUG. So you can't use PUT or DELETE with an extensionless url if you don't replace the handler. Something you would want to do with a RESTful Web API. The new handler registers for all verbs, and that includes PUT and DELETE.

ExtensionlessUrlHandler-Integrated-4.0 in IIS

There are a total of 3 ExtensionlessUrlHandlers. These are part of ASP.NET v4.0. On older machine's you have to install a KB/QFE to enable MVC (and WebForms?) to handle extensionless URLs, which wasn't possible in the previous version. See this link for more information.