WWDC21 Building a Great App: Export fails

Yes, I know WWDC21 was a long time ago but here it is August 2023 and I am looking at the "Building a Great App with SwiftUI. Following along with the Session 1 and 2 videos, I get to the part where you add an Export command. Only, the Export dialog does not appear. The "completed" session 2 source also fails to display an Export dialog. In fact there appears to be no definition for an Export view. I've searched the web, including the Apple forum, for this problem but it looks like no one has encountered this bug. Did anyone ever get this Great App to work?