What is the new GlobalSection in a VS2017 15.3 solution file? : <p>After upgrading to Visual Studio 2017 15.3.1 and ASP.NET Core 2.0, my solution file now has this at the end:</p>

<pre><code>GlobalSection(ExtensibilityGlobals) = postSolution
    SolutionGuid = {...a GUID...}
EndGlobalSection
</code></pre>

<p>What is this, and do I need it?</p>
