[MSBuildExtras] Using msbuild extras under linux fails with missing Microsoft.WinFX.props

MSBuild extras validates that projects can successfully build under a variety of .NET Runtimes and OSes, and a recent addition of validation of .NET Core 3.1 fails the build under Linux with the following error:

/__t/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk.WindowsDesktop/targets/Microsoft.NET.Sdk.WindowsDesktop.props(208,3): 
error MSB4019: The imported project "/__t/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk.WindowsDesktop/targets/Microsoft.WinFX.props" was not found. 
Confirm that the expression in the Import declaration "Microsoft.WinFX.props" is correct, and that the file exists on disk.

This error does not happen with .NET Core 3.0 and 2.2.

The error happens when building this project, with this script.

[Nirmal4G]

It seems the fix is not merged into SDK 3.1.302! So, I’ve asked whether it is possible for back porting the fix into 3.1.

[mfkl]

just a limitation of the fact that building projects targeting UAP isn’t supported on Linux.

That’s not it, you can reproduce with just

<Project Sdk="MSBuild.Sdk.Extras">
    <PropertyGroup>
        <TargetFramework>netstandard2.0</TargetFramework>
    </PropertyGroup>
</Project>