diff --git a/doc/world_format.txt b/doc/world_format.txt
index 9255fa8c0..5be1f3913 100644
--- a/doc/world_format.txt
+++ b/doc/world_format.txt
@@ -312,7 +312,7 @@ if map format version >= 23:
     u32 num_vars
     foreach num_vars:
       u16 key_len
-      u8[name_len] key
+      u8[key_len] key
       u32 val_len
       u8[val_len] value
       serialized inventory