System.Collections.NonGeneric is missed in NetStandard Library over 1.3
<p>Following url points the version 4.0.0, System.Collections.NonGeneric is exist after NetStandard 1.2</p>

<p><a href="https://github.com/dotnet/corefx/blob/master/Documentation/architecture/net-platform-standard.md" rel="nofollow">https://github.com/dotnet/corefx/blob/master/Documentation/architecture/net-platform-standard.md</a></p>

<p>but in Nuget site NetStandard does not have System.Collections.NonGeneric.</p>

<p><a href="https://www.nuget.org/packages/NETStandard.Library/" rel="nofollow">https://www.nuget.org/packages/NETStandard.Library/</a></p>

<p>Why NetStandard 1.3 and higher version does not have System.Collections.NonGeneric?</p>