PEP 728: Wording updates for clarity in certain sections (#3724)

peps/pep-0728.rst

@@ -654,9 +654,9 @@ because such dict can be a subtype of dict::
 How to Teach This
 =================
 
-The choice of ``"__extra_items__"`` and the requirement of ``closed=True``
-whenever it is used as a special key intended to make it more understandable to
-new users even without former knowledge of this feature.
+The choice of the spelling ``"__extra_items__"`` is intended to make this
+feature more understandable to new users compared to shorter alternatives like
+``"__extra__"``.
 
 Details of this should be documented in both the typing spec and the
 :mod:`typing` documentation.
@@ -701,9 +701,10 @@ subtyping. ``closed=True`` plays a similar role in the current proposal.
 Supporting ``TypedDict(extra=type)``
 ------------------------------------
 
-While this design is potentially viable, there are several partially addressable
-concerns to consider. The author of this PEP thinks that it is slightly less
-favorable than the current proposal.
+During the discussion of the PEP, there were strong objections against adding
+another place where types are passed as values instead of annotations from some
+authors of type checkers. While this design is potentially viable, there are
+also several partially addressable concerns to consider.
 
 - Usability of forward reference
   As in the functional syntax, using a quoted type or a type alias will be