--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ui/winui/MainWindow.idl	Tue Oct 10 10:58:14 2023 +0200
@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation and Contributors.
+// Licensed under the MIT License.
+
+namespace winui
+{
+    [default_interface]
+    runtimeclass MainWindow : Microsoft.UI.Xaml.Window
+    {
+        MainWindow();
+        Int32 MyProperty;
+    }
+}