diff --git a/Doc/library/json.rst b/Doc/library/json.rst
index 383ccad9df041b5..5e8c452a5ab9a1f 100644
--- a/Doc/library/json.rst
+++ b/Doc/library/json.rst
@@ -486,7 +486,7 @@ Encoders and Decoders
    +----------------------------------------+---------------+
    | Python                                 | JSON          |
    +========================================+===============+
-   | dict                                   | object        |
+   | dict, frozendict                       | object        |
    +----------------------------------------+---------------+
    | list, tuple                            | array         |
    +----------------------------------------+---------------+
@@ -504,6 +504,9 @@ Encoders and Decoders
    .. versionchanged:: 3.4
       Added support for int- and float-derived Enum classes.
 
+   .. versionchanged:: 3.15
+      Added support for :class:`frozendict`.
+
    To extend this to recognize other objects, subclass and implement a
    :meth:`~JSONEncoder.default` method with another method that returns a serializable object
    for ``o`` if possible, otherwise it should call the superclass implementation
diff --git a/Lib/calendar.py b/Lib/calendar.py
index 92fe6b7723fe268..7aaaf73bfe0044b 100644
--- a/Lib/calendar.py
+++ b/Lib/calendar.py
@@ -609,11 +609,11 @@ def formatyearpage(self, theyear, width=3, css='calendar.css', encoding=None):
         content = self.formatyear(theyear, width)
         return self._format_html_page(theyear, content, css, encoding)
 
-    def formatmonthpage(self, theyear, themonth, width=3, css='calendar.css', encoding=None):
+    def formatmonthpage(self, theyear, themonth, *, css='calendar.css', encoding=None):
         """
         Return a formatted month as a complete HTML page.
         """
-        content = self.formatmonth(theyear, themonth, width)
+        content = self.formatmonth(theyear, themonth)
         return self._format_html_page(theyear, content, css, encoding)
 
 
diff --git a/Lib/test/test_calendar.py b/Lib/test/test_calendar.py
index 15cce2b30da5768..f1bbee24cba1ca7 100644
--- a/Lib/test/test_calendar.py
+++ b/Lib/test/test_calendar.py
@@ -545,6 +545,12 @@ def test_format_html_year_with_month(self):
             result_2009_6_html
         )
 
+    def test_formatmonthpage_no_width(self):
+        # gh-140212: formatmonthpage must not accept a 'width' argument.
+        cal = calendar.HTMLCalendar()
+        self.assertIn(b'class="month">June 2009', cal.formatmonthpage(2009, 6))
+        self.assertRaises(TypeError, cal.formatmonthpage, 2009, 6, width=3)
+
 
 class CalendarTestCase(unittest.TestCase):
 
diff --git a/Lib/test/test_marshal.py b/Lib/test/test_marshal.py
index 9c4d91c456dc5d9..0e71d65f22b4f0d 100644
--- a/Lib/test/test_marshal.py
+++ b/Lib/test/test_marshal.py
@@ -386,6 +386,16 @@ def test_reference_loop_frozendict(self):
         for v in range(marshal.version + 1):
             self.assertRaises(ValueError, marshal.dumps, a, v)
 
+    def test_shared_reference_frozendict(self):
+        # A frozendict referenced more than once must round-trip with the
+        # shared identity preserved, like frozenset.
+        fd = frozendict({'a': 1, 'b': 2})
+        out = marshal.loads(marshal.dumps([fd, fd]))
+        self.assertEqual(out[0], fd)
+        self.assertIs(out[0], out[1])
+        nested = marshal.loads(marshal.dumps(frozendict({'x': fd, 'y': fd})))
+        self.assertIs(nested['x'], nested['y'])
+
     def test_loads_reference_loop_list(self):
         data = b'\xdb\x01\x00\x00\x00r\x00\x00\x00\x00' # [<R>]
         a = marshal.loads(data)
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-08-07-14-45-02.gh-issue-155315.Mk9Fd2.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-08-07-14-45-02.gh-issue-155315.Mk9Fd2.rst
new file mode 100644
index 000000000000000..a62059c0fa26160
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-08-07-14-45-02.gh-issue-155315.Mk9Fd2.rst
@@ -0,0 +1,3 @@
+Fix :mod:`marshal` so that a ``frozendict`` referenced more than once in the
+serialized data round-trips correctly, instead of failing to load with
+:exc:`ValueError`. Patch by tonghuaroot.
diff --git a/Misc/NEWS.d/next/Library/2026-07-06-10-30-00.gh-issue-153158.m0nthP.rst b/Misc/NEWS.d/next/Library/2026-07-06-10-30-00.gh-issue-153158.m0nthP.rst
new file mode 100644
index 000000000000000..3850860fb2f8db1
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-07-06-10-30-00.gh-issue-153158.m0nthP.rst
@@ -0,0 +1,3 @@
+Remove the erroneous *width* argument of
+:meth:`!calendar.HTMLCalendar.formatmonthpage`, which could drop the year from
+the heading.
diff --git a/Modules/_sre/sre.c b/Modules/_sre/sre.c
index e742a25e4891fce..031e972aeba0312 100644
--- a/Modules/_sre/sre.c
+++ b/Modules/_sre/sre.c
@@ -1273,8 +1273,7 @@ _sre_SRE_Pattern_split_impl(PatternObject *self, PyObject *string,
             );
         if (!item)
             goto error;
-        status = PyList_Append(list, item);
-        Py_DECREF(item);
+        status = _PyList_AppendTakeRef((PyListObject *)list, item);
         if (status < 0)
             goto error;
 
@@ -1283,8 +1282,7 @@ _sre_SRE_Pattern_split_impl(PatternObject *self, PyObject *string,
             item = state_getslice(&state, i+1, string, 0);
             if (!item)
                 goto error;
-            status = PyList_Append(list, item);
-            Py_DECREF(item);
+            status = _PyList_AppendTakeRef((PyListObject *)list, item);
             if (status < 0)
                 goto error;
         }
@@ -1301,8 +1299,7 @@ _sre_SRE_Pattern_split_impl(PatternObject *self, PyObject *string,
         );
     if (!item)
         goto error;
-    status = PyList_Append(list, item);
-    Py_DECREF(item);
+    status = _PyList_AppendTakeRef((PyListObject *)list, item);
     if (status < 0)
         goto error;
 
diff --git a/Objects/stringlib/split.h b/Objects/stringlib/split.h
index 0c11b7214e9b0b8..0b23b6430c8d636 100644
--- a/Objects/stringlib/split.h
+++ b/Objects/stringlib/split.h
@@ -4,6 +4,8 @@
 #error must include "stringlib/fastsearch.h" before including this module
 #endif
 
+#include "pycore_list.h"          // _PyList_AppendTakeRef()
+
 /* Overallocate the initial list to reduce the number of reallocs for small
    split sizes.  Eg, "A A A A A A A A A A".split() (10 elements) has three
    resizes, to sizes 4, 8, then 16.  Most observed string splits are for human
@@ -22,12 +24,8 @@
                         (right) - (left));      \
     if (sub == NULL)                            \
         goto onError;                           \
-    if (PyList_Append(list, sub)) {             \
-        Py_DECREF(sub);                         \
-        goto onError;                           \
-    }                                           \
-    else                                        \
-        Py_DECREF(sub);
+    if (_PyList_AppendTakeRef((PyListObject *)list, sub)) \
+        goto onError;
 
 #define SPLIT_ADD(data, left, right) {          \
     sub = STRINGLIB_NEW((data) + (left),        \
@@ -37,12 +35,8 @@
     if (count < MAX_PREALLOC) {                 \
         PyList_SET_ITEM(list, count, sub);      \
     } else {                                    \
-        if (PyList_Append(list, sub)) {         \
-            Py_DECREF(sub);                     \
+        if (_PyList_AppendTakeRef((PyListObject *)list, sub)) \
             goto onError;                       \
-        }                                       \
-        else                                    \
-            Py_DECREF(sub);                     \
     }                                           \
     count++; }
 
diff --git a/Python/marshal.c b/Python/marshal.c
index 603697e9081c59a..b11f2dca57a226c 100644
--- a/Python/marshal.c
+++ b/Python/marshal.c
@@ -1505,6 +1505,7 @@ r_object(RFILE *p)
         }
         if (type == TYPE_FROZENDICT && v != NULL) {
             Py_SETREF(v, PyFrozenDict_New(v));
+            v = r_ref_insert(v, idx, flag, p);
         }
         retval = v;
         break;