I've done two playthroughs using the Ringworld Empire origin, and in both the special project "Lost Technologies: Superior Designs" doesn't work - the research button is always greyed out.
To bypass this, I used the console command "finish_special_projects" but to no avail. The pop-up shows up as in to confirm the project is finished and giving a research option, but the research isn't in the queue and the project goes back to being unfinished with the greyed out button.
The tech is missing from the files maybe? Any help with this?