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
Many answers are outdated (pre-Microsoft acquisition/free private repos). This one was written after the announcement of free private repos.
Github pages are not available on free private repos for individuals, as shown in the repo settings:
2020 (most basic plan is now "Team"):
All pages are public, even if you upgrade. Upgrading only enables the Pages feature on private repos, just like it enables other features. The Pages feature is publicly available static web hosting.