Actually *do* override the type in AppBuilder.
diff --git a/Lib/plat-mac/bundlebuilder.py b/Lib/plat-mac/bundlebuilder.py
index cd370fd..9e4fc91 100755
--- a/Lib/plat-mac/bundlebuilder.py
+++ b/Lib/plat-mac/bundlebuilder.py
@@ -291,7 +291,7 @@
 class AppBuilder(BundleBuilder):
 
 	# Override type of the bundle.
-	type = "BNDL"
+	type = "APPL"
 
 	# platform, name of the subfolder of Contents that contains the executable.
 	platform = "MacOS"