It seems to me I am unable to download the Windows build from a Linux computer. On the atom.io homepage, I see Download .deb and Download .rpm buttons, together with a smaller Other platforms link. However, the Other platforms link leads to the FAQ page, where no downloads are to be found, only the information that “Prebuilt versions of Atom are available for OS X 10.8 or later, Windows 7 & 8, RedHat Linux, and Ubuntu Linux.”
I managed to make the download by guessing the download URL, but that was not very convenient.
Or, is this an intentional limitation? (I admit this use case is not very common (assuming the client OS detection works correctly), I could have used a Windows machine for the download.)