ILSpy
.NET Decompiler with support for PDB generation, ReadyToRun, Metadata
...In Visual Studio 2019, you have to manually enable F12 support. Go to Tools / Options / Text Editor / C# / Advanced and check Enable navigation to decompiled source. C# for Visual Studio Code ships with decompilation support as well. To enable, activate the setting "Enable Decompilation Support. ILSpy is distributed under the MIT License. Please see the About doc for details, as well as third-party notices for included open-source libraries. Visual Studio 16.3 and later include a version of the .NET (Core) SDK that is managed by the Visual Studio installer - once you update, it may get upgraded too. ...