Couldn\'t find anything in the github documentation and also here on SO. But I was wondering if there could be a http://foo.github.com for a private repository
The page.github.com does mention:
Github Pages are hosted free and easily published through our site,
Without ever mentioning access control.
The GitHub page help doesn't mention any ACL either.
They are best managed in a gh-pages branch, and can be managed in their own submodule.
But again, without any restriction in term of visibility once published by GitHub.