What have we learned so far about Crew Dragon’s cupola, the largest window to ever fly to space

In less than two weeks, the ground-breaking Inspiration4 mission is scheduled to launch a Crew Dragon spacecraft into orbit with four crew members, none of whom are professional astronauts. Crew Dragon for this mission is equipped with a glass cupola to give the crew the best possible view during their three-day stay in Earth orbit. What have we learned so far about the largest window to ever be flown to space?