It looks like with JUCE 5, Visual Studio projects are structured differently.
The .cpp and .h files for my project are all in the folder ending in _App, which is fine, but the same files also appear in the other folders in the solution. For example, Controller.cpp is also in the AudioPatchbay folder. It works fine - I was just wondering about the reason for the duplication.
I do like that it defaults to an x64 build now; that’s a big improvement.