expand on uids

source/release-notes/v4.0-release-notes.rst

@@ -241,6 +241,11 @@ User mapping scripts can now return a UID instead of a username.
 This is particularly useful for centers that have multiple domains where
 username collisions may occur.
 
+For example if the two users ``annie.oakley@osc.edu`` and ``annie.oakley@caltech.edu``
+both *incorrectly* map to the user ``annie.oakley``, you will now be able to return
+the unique number that is their UID (User Identifier) and therefore have
+no collisions.
+
 
 Interactive Apps Can Have a Text Header.
 ........................................