When building standalone wheels for macOS and defining the deployment target explicitly, the resulting wheel filenames are e.g.:
In this case, I used Python from python.org (built on macOS 10.6) but I defined the deployment target to be macOS 10.10 (--osx-deployment-target=10.10).
So the filenames inherit the platform used when building Python, not the deployment target platform. I would propose the built wheels should instead be named (or renamed) into saying the following in my particular scenario described here: