This is actually failed attempt to make something waterproof. You can tweak settings and create various gaskets or other types of sealing to make it work.
I was able to make it waterproof only to a few meters. The design is actually not very good.
Don't forget to read my article to find out more: https://blog.prusaprinters.org/watertight-3d-pr…ing-part-2_53638/
The author hasn't provided the model origin yet.