--- a/src/pyams_utils/interfaces/site.py	Mon Mar 02 23:58:31 2015 +0100
+++ b/src/pyams_utils/interfaces/site.py	Tue Mar 03 16:29:48 2015 +0100
@@ -56,3 +56,7 @@
 
     This factory may be loaded through an adapter
     """
+
+
+class IOptionalUtility(Interface):
+    """Marker interface for site utilities that can be removed"""