From the front page it says python and gcc is included, but I don't see anything about the gcc (or python, but python isn't gpl) source on their legal page:
Did anyone have a look? Do they distribute the kernel, or run on top of Android? At a glance it appears they're playing a bit loose with the licenses - but maybe they have a link/offer of source in the download?
This is interesting. They're running Debian 8 inside an LXC container, which I've personally never seen before on Android. Not sure how they're doing the HDMI interface though - I assume it's an app, but couldn't find it in either one of the images.