GitHub.io is a domain that GitHub offers to users for hosting static websites directly from their repositories. Because it is a legitimate platform used by millions of developers for portfolios, documentation, and demos, network filters often overlook it. Clever developers have taken advantage of this by hosting simple HTML5, JavaScript, or Flash game emulators (like those for classic arcade, NES, or browser-based puzzle games) on GitHub.io pages. When a game is hosted there, it often bypasses typical web filters, hence the term "unblocked."
When people search for "github io games unblocked install," they often mean one of two things. Let's clarify the distinction. github io games unblocked install
If you want to play the game without an internet connection—perhaps to bypass a firewall entirely—you can "install" the source code. GitHub