Developer activity is a small module that I just released on Drupal.org. It fetches local users activities on Drupal.org and on GitHub.com into custom entities.
Only public endpoints are used and they at each cron. So all you need are a Drupal.org user ID and a GitHub.com user name fields for your Drupal users (and of course install the dependencies, which is just Migrate plus 8.x-5.x.
You can then create Views with those custom entities, for instance.
This module is not a big deal, really, but I thought it could be valuable for other developers websites. Also, it's always interesting to have new Migrate API examples to have a look at. The Atom feed migration was especially annoying with namespace problems; ultimately I had to fallback to using local-name and would be interested if anyone has a clue to fix this (I tried quite some time and no online solution was working for me).
This is a great project Guillaume!
Thanks a lot Ed!!!