Where is my ASP.net Core 2.0 Project.json file?

Microsoft decided to move away from project.json. The reasons are given here:

https://blogs.msdn.microsoft.com/dotnet/2016/05/23/changes-to-project-json/

Here is a description of how to map your json to a csproj file:

https://docs.microsoft.com/en-us/dotnet/core/tools/project-json-to-csproj