This website has some nice explanations and GIFs: https://s2.smu.edu/propulsion/Pages/variations.htm

So the "open rotor" engine is actually a propfan engine?

Essentially yes, different engine companies have used different nomenclature over time. It seems that the "open rotor" terminology is being used to emphasize the improvements which have been made to blade design, noise, and general efficiency.

The inner nerd in me is so satisfied. Thanks for the link.

That website it gold!

I think it is the stators fixed to the engine nacelle, judging by the article image.