Why is the platform called win32 and not win64 if Windows is already 64-bit

Well so apparently I learned something new today. There is no commonly used term for platforms that are Windows 64-bit with explicit 64 in the name. win32 refers to the API from Windows 95 and because of the backward compatibility and because it didn't really change since then, it is still used as win32, not win or win64. So I assume Electron uses win32 under the hood, not UWP or winRT?