How would Google treat a GitHub-Pages site, that is based on the same content as the GitHub repository itself?

I’ve just created a GitHub Pages "site", out of one of my repositories on Github. Basically it’s just a landing page, that pretty-prints my file(that is found in the repo). GitHub allows you to create such a site automatically.

I don’t know too much about SEO, but i’ve heard that google takes into account "duplicate" content, as a "devaluation" factor.

So i was wondering: If google finds a Github repo page, that outputs some file, and then finds a Pages) page, that has almost the identical content- would it treat it as some duplicate, and apply some kind of penalty to it?