IMainWindow mainWindow = new MainWindow();
mainWindow.Title = "My Application";
mainWindow.Show();In this example, we show the main window using the Show method. Package/Library: This would depend on the implementation details of the MainWindow class. In general, IMainWindow is often used in GUI frameworks such as WPF and WinForms to provide a common interface for working with the main application window. The package/library used would depend on the specific framework being used.