This mentioned in visual demo but not in specs. Is this required?

From Udacity Mentor:
Your project structure looks good, but I encourage you to have a look at 2 architecture below. Actually, I'm using Clean Swift for my current projects

https://hackernoon.com/introducing-clean-swift-architecture-vip-770a639ad7bf
https://medium.com/@smalam119/viper-design-pattern-for-ios-application-development-7a9703902af6
And this is the project structure I used for this project

From Udacity Mentor:
You can add a Navigation Bar to the TabBar and add a TabBarViewController to that TabBar.
With the buttons in the TabBar you can process them in the TabBarViewController

class TabBarLocationsViewController: UITabBarController {
@IBAction func onClickRefreshButton(_ sender: Any) {
onRefreshData()
}
@IBAction func onClickAddButton(_ sender: Any) {
}
}