When using the UITabBarController in iOS 15, why does the background color of the tabBar appear black?

edit

The background color of the tabBar appearing black in iOS 15 is likely because of the new UIBarAppearance feature in iOS 15. In iOS 15, the default UIBarAppearance for tab bars is a black color. To change the background color of the tab bar, you can set the backgroundColor property of the tabBar using the appearance() method of the UITabBar class. For example:

// Set the background color of the tab bar to red
UITabBar.appearance().backgroundColor = UIColor.red