diff --git a/pep-0634.rst b/pep-0634.rst
index aa1f7f9ee..67c058f64 100644
--- a/pep-0634.rst
+++ b/pep-0634.rst
@@ -418,7 +418,9 @@ A mapping pattern fails if the subject value is not an instance of
 ``collections.abc.Mapping``.
 
 A mapping pattern succeeds if every key given in the mapping pattern
-matches the corresponding item of the subject mapping.  If a ``'**'
+is present in the subject mapping, and the pattern for 
+each key matches the corresponding item of the subject mapping. Keys
+are always compared with the ``==`` operator.  If a ``'**'
 NAME`` form is present, that name is bound to a ``dict`` containing
 remaining key-value pairs from the subject mapping.