diff --git a/Doc/library/urllib.request.rst b/Doc/library/urllib.request.rst
index 9274a0c88ac4c8..7a0ccfd024beb3 100644
--- a/Doc/library/urllib.request.rst
+++ b/Doc/library/urllib.request.rst
@@ -1056,6 +1056,10 @@ AbstractBasicAuthHandler Objects
    authenticate for, *req* should be the (failed) :class:`Request` object, and
    *headers* should be the error headers.
 
+   *headers* must be a mapping-like object with case-insensitive lookup
+   that implements the ``get_all()`` method,
+   such as :class:`email.message.Message` or :class:`wsgiref.headers.Headers`.
+
    *host* is either an authority (e.g. ``"python.org"``) or a URL containing an
    authority component (e.g. ``"https://python.org/"``). In either case, the
    authority must not contain a userinfo component (so, ``"python.org"`` and
@@ -1097,6 +1101,9 @@ AbstractDigestAuthHandler Objects
    should be the (failed) :class:`Request` object, and *headers* should be the
    error headers.
 
+   *headers* must be a mapping-like object with case-insensitive lookup,
+   such as :class:`email.message.Message` or :class:`wsgiref.headers.Headers`.
+
 
 .. _http-digest-auth-handler:
 
diff --git a/Include/internal/pycore_interpframe.h b/Include/internal/pycore_interpframe.h
index 812e1a28debef4..a85fa9bd32853c 100644
--- a/Include/internal/pycore_interpframe.h
+++ b/Include/internal/pycore_interpframe.h
@@ -345,7 +345,7 @@ _PyFrame_GetFrameObject(_PyInterpreterFrame *frame)
 {
 
     assert(!_PyFrame_IsIncomplete(frame));
-    PyFrameObject *res = FT_ATOMIC_LOAD_PTR_ACQUIRE(frame->frame_obj);
+    PyFrameObject *res = (PyFrameObject*)FT_ATOMIC_LOAD_PTR_ACQUIRE(frame->frame_obj);
     if (res != NULL) {
         return res;
     }
diff --git a/Lib/concurrent/futures/process.py b/Lib/concurrent/futures/process.py
index c130259acb737a..7f4f225c0ad4fb 100644
--- a/Lib/concurrent/futures/process.py
+++ b/Lib/concurrent/futures/process.py
@@ -119,10 +119,11 @@ def _python_exit():
 
 
 # On Windows, WaitForMultipleObjects is used to wait for processes to finish.
-# It can wait on, at most, 63 objects. There is an overhead of two objects:
+# It can wait on, at most, 64 objects. There is an overhead of three objects:
 # - the result queue reader
 # - the thread wakeup reader
-_MAX_WINDOWS_WORKERS = 63 - 2
+# - the SIGINT handler
+_MAX_WINDOWS_WORKERS = 64 - 3
 
 # Hack to embed stringification of remote traceback in local traceback
 
diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
index df473d59fff3d8..959732fc6e4a83 100644
--- a/Lib/test/test_compile.py
+++ b/Lib/test/test_compile.py
@@ -63,6 +63,30 @@ def test_argument_handling(self):
         self.assertRaises(SyntaxError, exec, 'def f(a = 0, a = 1): pass')
         self.assertRaises(SyntaxError, exec, 'def f(a): global a; a = 1')
 
+    def test_call_opcode_stack_use_limit(self):
+        def get_call_opcode(positional_count, keyword_count):
+            args = ["0"] * positional_count
+            args.extend(f"a{i}=0" for i in range(keyword_count))
+            code = compile(f"f({', '.join(args)})", "<test>", "exec")
+            return next(
+                instr.opname for instr in dis.get_instructions(code)
+                if instr.opname.startswith("CALL")
+            )
+
+        for positional_count, keyword_count, expected_opcode in [
+            (0, 16, "CALL_KW"),
+            (15, 14, "CALL_KW"),
+            (15, 15, "CALL_FUNCTION_EX"),
+        ]:
+            with self.subTest(
+                positional_count=positional_count,
+                keyword_count=keyword_count,
+            ):
+                self.assertEqual(
+                    get_call_opcode(positional_count, keyword_count),
+                    expected_opcode,
+                )
+
     def test_syntax_error(self):
         self.assertRaises(SyntaxError, compile, "1+*3", "filename", "exec")
 
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-08-14-19-00-00.gh-issue-155141.call-kw.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-08-14-19-00-00.gh-issue-155141.call-kw.rst
new file mode 100644
index 00000000000000..caee6e10168eab
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-08-14-19-00-00.gh-issue-155141.call-kw.rst
@@ -0,0 +1,3 @@
+Compile pure-keyword calls with 16 to 29 keyword arguments using the faster
+``CALL_KW`` instruction.  This includes common cases such as dataclass
+constructors with many fields.
diff --git a/Python/codegen.c b/Python/codegen.c
index 79b84f13e629c7..e2ef40b4e30490 100644
--- a/Python/codegen.c
+++ b/Python/codegen.c
@@ -87,6 +87,9 @@ typedef _PyCompile_FBlockInfo fblockinfo;
 
 #define LOC(x) SRC_LOCATION_FROM_AST(x)
 
+#define CALL_STACK_USE(nargs, nkwds) \
+    ((nargs) + (nkwds) + ((nkwds) != 0))
+
 #define NEW_JUMP_TARGET_LABEL(C, NAME) \
     jump_target_label NAME = _PyInstructionSequence_NewLabel(INSTR_SEQUENCE(C)); \
     if (!IS_JUMP_TARGET_LABEL(NAME)) { \
@@ -4147,7 +4150,7 @@ maybe_optimize_method_call(compiler *c, expr_ty e)
     /* Check that there aren't too many arguments */
     argsl = asdl_seq_LEN(args);
     kwdsl = asdl_seq_LEN(kwds);
-    if (argsl + kwdsl + (kwdsl != 0) >= _PY_STACK_USE_GUIDELINE) {
+    if (CALL_STACK_USE(argsl, kwdsl) >= _PY_STACK_USE_GUIDELINE) {
         return 0;
     }
     /* Check that there are no *varargs types of arguments. */
@@ -4440,7 +4443,7 @@ codegen_call_helper_impl(compiler *c, location loc,
     nelts = asdl_seq_LEN(args);
     nkwelts = asdl_seq_LEN(keywords);
 
-    if (nelts + nkwelts*2 > _PY_STACK_USE_GUIDELINE) {
+    if (CALL_STACK_USE(nelts, nkwelts) > _PY_STACK_USE_GUIDELINE) {
          goto ex_call;
     }
     for (i = 0; i < nelts; i++) {