diff --git a/pep-0640.rst b/pep-0640.rst
index 09f86a7bc..471079da1 100644
--- a/pep-0640.rst
+++ b/pep-0640.rst
@@ -132,6 +132,8 @@ Backwards Compatibility
 Introducing a new token means there are no backward compatibility concerns.
 No valid syntax changes meaning.
 
+"?" is not considered an identifier, so str.isidentifier() does not change.
+
 The AST does change in an incompatible way, as the identifier of a Name
 token can now be empty. Code using the AST will have to be adjusted
 accordingly.