What are .NET Platform Extensions on docs.microsoft.com? : <p>There is a framework-level navigation element at Microsoft Docs called <a href="https://docs.microsoft.com/en-us/dotnet/api/index?view=dotnet-plat-ext-2.1" rel="noreferrer">".NET Platform Extensions"</a>. It contains docs on recently added APIs like <code>System.IO.Pipelines</code> and <code>System.Threading.Channels</code> for example, as well as a whole bunch of other APIs, including the not-so-recent ones.</p>

<p>Some APIs from this collection are available as nuget packages (for both .Net Core and .Net Framework), but others are not seemingly available. Also, as of now, there is no nuget package called ".NET Platform Extensions" or anything similar.</p>

<p>So, the question is what exactly does this collection of APIs represent? What is it's relationship to each of the following:</p>

<ul>
<li>.Net Framework</li>
<li>.Net Core</li>
<li>.Net Standard</li>
</ul>

<p>What about support in the .Net Framework / .Net Core?</p>

<p>Finally, some APIs seem to be already available as separate nuget packages, others are yet to be made available, so what is the story in that regard?</p>
