This is the PEP 503-style "simple" API to this collection of prototype "pybi" Python interpreter builds. So far it's just CPython, though it'd be cool to get PyPy in here too, maybe even Cinder or Pyston.
The Windows builds are repacked versions of the official Nuget packages maintained by Steve Dower.
The macOS builds are repacked versions of the official Python.org framework packages, that have been run through Greg Neagle's "relocatablizer" (see https://github.com/gregneagle/relocatable-python).
The Linux builds are custom-built using the same scripts that are used to generate the interpreters included in the official manylinux2014 (CentOS 7-based) docker image. (TODO: add musllinux builds too.)