diff --git a/src/NoPELib/expansionsLib.py b/src/NoPELib/expansionsLib.py
index 2c6c16b..726d244 100644
--- a/src/NoPELib/expansionsLib.py
+++ b/src/NoPELib/expansionsLib.py
@@ -36,6 +36,7 @@ class Expansion:
     Attributes:
         players (tuple of str): 
         tags (tuple of flag): 
+        config: The config of the expansion. Can't be modified during execution.
 
     Methods:
         step: 
@@ -57,6 +58,10 @@ class Expansion:
     
     @property
     def config(self):
+        """
+        The config of the expansion.
+        NOTE Can't be modified during execution.
+        """
         return copy.deepcopy(self._manager.config[self._ID]["config"])
 
     @property