The tool dxc is the DirectX Shader Compiler used in Train Simulator NEXT.
The tool is located in the [root]/Tools/ directory.
Usually, you do not need to use this tool. It is provided by us if needed.
For further information read the help provided by the tool, read the official manual on https://github.com/microsoft/DirectXShaderCompiler/wiki/Using-dxc.exe-and-dxcompiler.dll or a description about its flags on https://simoncoenen.com/blog/programming/graphics/DxcCompiling.
