I just bought a Pro with nothing pre-installed. I got the kit though, so the SSD was on its own box, still unopened. Maybe they pre-install if you buy it assembled?
In any case, you probably got stock Ubuntu. Anything different from that would mean you have no chance of reinstalling it and getting the same experience, or installing Fedora (which is also officially supported) and getting the same.
Why? Companies that sell Windows laptops absolutely have these figured out for various customizations they want. Those are usually shit customizations to be fair, but in this case it'd be actually useful.
