diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 181bd351b46..c2deaadd6e6 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -1253,6 +1253,7 @@ options 	MAC
 options 	MAC_BIBA
 options 	MAC_BSDEXTENDED
 options 	MAC_DDB
+options 	MAC_DO
 options 	MAC_IFOFF
 options 	MAC_IPACL
 options 	MAC_LOMAC