title: How to tell if code is written for regular .NET or .NET Core?
body: <p>I work with a code base that contains some code in regular .NET and some code in .NET Core. When I open an individual .cs file, I'm not always sure whether the file was meant to be compiled with regular .NET or .NET Core. Obviously, there's a lot of overlap between both frameworks -- and a lot of code can be run unmodified in both frameworks.</p>
  
  <p>So my question is, what are some easy ways to determine whether a .cs file is intended to be compiled for regular .NET or .NET Core? </p>
  
  <p>(I imagine that looking for certain usings that only exist in one framework or the other is probably the biggest telltale sign. If that is indeed the way to determine this, is there a web page which lists which usings are exclusive to regular .NET vs. .NET Core?)</p>