Works. I've downloaded Git-1.7.10-preview20120409.exe from Google Code, installed with defaults setup options, and started it successfully. It opens a bash shell window where you have but to type the following command:
git clone
https://github.com/fhaby/whatever
It will download a copy of the repository. You'll need to read the "Installation" chapter in the documentation included in the "whatever-docs.zip" file before running the Windows exe (it will complain about Lua not being installed if you run it straight out-of-the-box). I've updated the README file to warn about that.
Actually there's a few open source tools (Lua for Windows, WxLua, TeXLua or ConTeXt, and Info-Zip) that are required depending on whether you intend to build ePUB or PDF, so you should know about that before installing.
As for Git Hub, this is a deliberate choice over say sourceforge, over whose copyright policy I have questions , I don't intend to move somewhere else for the time being.