Today Doug Mahugh, Senior Technical Evangelist for Microsoft Open Technologies Inc., announced the release of an Open XML SDK as an open source project through the MS Open Tech hub. Although the SDK has been available since 2007, this release includes full source code available under the Apache 2.0 license on GitHub, as well as the project will continue to grow under the stewardship of the .NET Foundation

Firefox 55: first desktop browser to support WebVR 

So yes, Web API will return dynamic types. This isn't a surprise given that it needs to support any model type that we would normally throw at it. 

Target Framework             Default for AnalysisLevel
net5.0                       5
netcoreapp3.1 or lower       4
netstandard2.1 or lower      4
.NET Framework 4.8 or lower  4

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <!-- get more advanced warnings for this project -->
    <AnalysisLevel>5</AnalysisLevel>
  </PropertyGroup>
</Project>

<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <!-- be automatically updated to the newest stable level -->
    <AnalysisLevel>latest</AnalysisLevel>
  </PropertyGroup>
</Project>

<AnalysisLevel>preview</AnalysisLevel>

<!-- I am just fine thanks -->
<AnalysisLevel>none</AnalysisLevel>

<PropertyGroup>
  <AnalysisMode>AllEnabledByDefault</AnalysisMode>
</PropertyGroup>

<PropertyGroup>
   <CodeAnalysisTreatWarningsAsErrors>false</CodeAnalysisTreatWarningsAsErrors>
</PropertyGroup>

<PropertyGroup>
   <EnableNETAnalyzers>true</EnableNETAnalyzers>
</PropertyGroup>

<PropertyGroup>
   <EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
</PropertyGroup>

<Project>
  <PropertyGroup>
    <AnalysisLevel>latest</AnalysisLevel>
    <AnalysisMode>AllEnabledByDefault</AnalysisMode>
    <CodeAnalysisTreatWarningsAsErrors>true</CodeAnalysisTreatWarningsAsErrors>
    <EnableNETAnalyzers>true</EnableNETAnalyzers>
    <EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
  </PropertyGroup>
</Project>

    [Flags]
public enum MiniDumpType
{
    MiniDumpNormal = 0x00000000,
    MiniDumpWithDataSegs = 0x00000001,
    MiniDumpWithFullMemory = 0x00000002,
    MiniDumpWithHandleData = 0x00000004,
    MiniDumpFilterMemory = 0x00000008,
    MiniDumpScanMemory = 0x00000010,
    MiniDumpWithUnloadedModules = 0x00000020,
    MiniDumpWithIndirectlyReferencedMemory = 0x00000040,
    MiniDumpFilterModulePaths = 0x00000080,
    MiniDumpWithProcessThreadData = 0x00000100,
    MiniDumpWithPrivateReadWriteMemory = 0x00000200,
    MiniDumpWithoutOptionalData = 0x00000400,
    MiniDumpWithFullMemoryInfo = 0x00000800,
    MiniDumpWithThreadInfo = 0x00001000,
    MiniDumpWithCodeSegs = 0x00002000,
    MiniDumpWithoutManagedState = 0x00004000
}

public static class NativeMethods
{
    [DllImport("Dbghelp.dll")]
    public static extern bool MiniDumpWriteDump(
        IntPtr hProcess,
        int processId,
        IntPtr hFile,
        MiniDumpType dumpType,
        IntPtr exceptionParam,
        IntPtr userStreamParam,
        IntPtr callbackParam);
}

public static class DebugInfo
{
    public static void CreateMiniDump(
        string dumpFileName, MiniDumpType dumpType = MiniDumpType.MiniDumpNormal)
    {
        using (var stream = File.Create(dumpFileName))
        {
            var process = Process.GetCurrentProcess();
            // It is safe to call DangerousGetHandle() here because the process is already crashing.
            NativeMethods.MiniDumpWriteDump(
                            process.Handle,
                            process.Id,
                            stream.SafeFileHandle.DangerousGetHandle(),
                            dumpType,
                            IntPtr.Zero,
                            IntPtr.Zero,
                            IntPtr.Zero);
        }
    }
 
    public static void CreateMiniDump(MiniDumpType dumpType = MiniDumpType.MiniDumpNormal)
    {
        const string dateFormat = "yyyy-MM-dd-HH-mm-ss-fffZ"; // Example: 2010-09-02-09-50-43-341Z
        var thisAssembly = Assembly.GetEntryAssembly() ?? Assembly.GetCallingAssembly();
        var dumpFileName = string.Format(@"{0}-MiniDump-{1}.dmp",
                    thisAssembly.GetName().Name,
                    DateTime.UtcNow.ToString(dateFormat, CultureInfo.InvariantCulture));
 
        var path = Path.Combine(getApplicationPath(), dumpFileName);
        CreateMiniDump(path, dumpType);
    }
 
    private static string getApplicationPath()
    {
        return HttpContext.Current != null ?
            HttpRuntime.AppDomainAppPath :
            Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
    }
}

class Program
{
    static void Main(string[] args)
    {
        try
        {
            var zero = 0;
            Console.WriteLine(1 / zero);
        }
        catch (Exception ex)
        {
            Console.Write(ex);
            DebugInfo.CreateMiniDump(dumpType:
                                MiniDumpType.MiniDumpNormal |
                                MiniDumpType.MiniDumpWithPrivateReadWriteMemory |
                                MiniDumpType.MiniDumpWithDataSegs |
                                MiniDumpType.MiniDumpWithHandleData |
                                MiniDumpType.MiniDumpWithFullMemoryInfo |
                                MiniDumpType.MiniDumpWithThreadInfo |
                                MiniDumpType.MiniDumpWithUnloadedModules);
 
            throw;
        }
    }
}