How does github pages serve files?

My understanding on how Web hosting works is that you require some sort of technology to serve content, even if it's just an HTML file. I thought that simply putting an html file on a server running nothing at all (no Apache, etc), and going to {server_ip}/path/to/.html will not serve it over http.

So I've Googled and to no avail, I cannot find out what technology github pages is using to serve static pages