That is for interpolating the Wizard field into the text of the generated post.
Yeah, the interaction between Locations and Calendar & Events isn’t great. @merefield did a brilliant job of integrating Locations and the Custom Wizard Plugin, but integrating Locations with Calendar & Events (since the new Location functionality of it) hasn’t happened yet.
I’d advise forgetting about using the Locations plugin for Calendar & Event for now, and if it is important to you that you liaise with @merefield about sponsoring development of it in future.