diff --git a/lib/constants.py b/lib/constants.py
index 7716d8e9808a03b1bdfcf6b656f82e30f75d3463..5c39a44d345d203ea3d52ffb4b5a4e0bab30bd98 100644
--- a/lib/constants.py
+++ b/lib/constants.py
@@ -972,7 +972,7 @@ QFT_ALL = frozenset([
 QRFS_NORMAL = 0
 #: Unknown field
 QRFS_UNKNOWN = 1
-#: No data
+#: No data (e.g. node offline)
 QRFS_NODATA = 2
 #: Value unavailable for item
 QRFS_UNAVAIL = 3