diff --git a/BaseClasses.py b/BaseClasses.py
index b40b872f0c..7eb40028cc 100644
--- a/BaseClasses.py
+++ b/BaseClasses.py
@@ -1206,7 +1206,10 @@ class Location:
 class ItemClassification(IntFlag):
     filler = 0b0000  # aka trash, as in filler items like ammo, currency etc,
     progression = 0b0001  # Item that is logically relevant
-    useful = 0b0010  # Item that is generally quite useful, but not required for anything logical
+    # Protects this item from being placed on excluded or unreachable locations.
+    useful = 0b0010  # Item that is especially useful.
+    # Protects this item from being placed on excluded or unreachable locations.
+    # When combined with another flag like "progression", it means "an especially useful progression item".
     trap = 0b0100  # detrimental item
     skip_balancing = 0b1000  # should technically never occur on its own
     # Item that is logically relevant, but progression balancing should not touch.