The plaza isn't technically part of the project. It's currently lanes of traffic that connect Harbour St to Lake Shore that are planned to be removed. It's a low volume stretch but, I can't say I'm a fan of the idea of losing this direct connection.
https://www.google.ca/maps/place/Google+...6f636e8e5!8m2!3d43.6503522!4d-79.3837951
There is some retail at grade. I suspect the higher value retail will be on the Plus 15 level.