I've just unlocked the Empire Development Deed "Endless Research Park and EndlessWorld". To complete it, I must build the aforementioned wonder in one of my star systems.
How do I build the "Endless Research Park and EndlessWorld" wonder?
I'm not seeing it in the list of improvements in the Star System Management Screen, nor do I see it as an option for system development at the moment...
Weirdly enough about an hour after I posted the question, it did show up in a star system. I think it may have been because the system was not developed to level 2 (modernization?). I'll test it again today.