diff --git a/src/backend/utils/misc/README b/src/backend/utils/misc/README
index 6e294386f7..6c69cad117 100644
--- a/src/backend/utils/misc/README
+++ b/src/backend/utils/misc/README
@@ -4,7 +4,9 @@ GUC Implementation Notes
 ========================
 
 The GUC (Grand Unified Configuration) module implements configuration
-variables of multiple types (currently boolean, enum, int, real, and string).
+variables of multiple types (currently boolean, enum, int, int64, real,
+and string).
+
 Variable settings can come from various places, with a priority ordering
 determining which setting is used.