diff --git a/misc/typeshed_patches/0001-Adjust-stubs-to-fix-mypy-lookup-error-due-to-circula.patch b/misc/typeshed_patches/0001-Adjust-stubs-to-fix-mypy-lookup-error-due-to-circula.patch
new file mode 100644
index 0000000000000..d8c4e24af917b
--- /dev/null
+++ b/misc/typeshed_patches/0001-Adjust-stubs-to-fix-mypy-lookup-error-due-to-circula.patch
@@ -0,0 +1,37 @@
+From 5c922a2484f2e18c7f901e62bb499b6414cf1090 Mon Sep 17 00:00:00 2001
+From: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
+Date: Wed, 18 Feb 2026 13:11:02 +0100
+Subject: [PATCH] Adjust stubs to fix mypy lookup error due to circular
+ dependencies in stubs
+
+---
+ mypy/typeshed/stdlib/time.pyi | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/mypy/typeshed/stdlib/time.pyi b/mypy/typeshed/stdlib/time.pyi
+index 64a009318..d0853792b 100644
+--- a/mypy/typeshed/stdlib/time.pyi
++++ b/mypy/typeshed/stdlib/time.pyi
+@@ -1,16 +1,16 @@
+ import sys
+ from _typeshed import structseq
+-from typing import Any, Final, Literal, Protocol, SupportsFloat, SupportsIndex, final, type_check_only
++from typing import Any, Final, Literal, Protocol, SupportsFloat, SupportsIndex, Union, final, type_check_only
+ from typing_extensions import TypeAlias
+ 
+ _TimeTuple: TypeAlias = tuple[int, int, int, int, int, int, int, int, int]
+ 
+ if sys.version_info >= (3, 15):
+     # anticipate on https://github.com/python/cpython/pull/139224
+-    _SupportsFloatOrIndex: TypeAlias = SupportsFloat | SupportsIndex
++    _SupportsFloatOrIndex: TypeAlias = Union[SupportsFloat, SupportsIndex]
+ else:
+     # before, time functions only accept (subclass of) float, *not* SupportsFloat
+-    _SupportsFloatOrIndex: TypeAlias = float | SupportsIndex
++    _SupportsFloatOrIndex: TypeAlias = Union[float, SupportsIndex]
+ 
+ altzone: int
+ daylight: int
+-- 
+2.53.0
+
diff --git a/misc/typeshed_patches/0001-Remove-use-of-LiteralString-in-builtins-13743.patch b/misc/typeshed_patches/0001-Remove-use-of-LiteralString-in-builtins-13743.patch
index b8d0d9812198a..3ca8f4deec922 100644
--- a/misc/typeshed_patches/0001-Remove-use-of-LiteralString-in-builtins-13743.patch
+++ b/misc/typeshed_patches/0001-Remove-use-of-LiteralString-in-builtins-13743.patch
@@ -1,14 +1,14 @@
-From ed11d7e0204868ef1a43c17ed950372b1d78f497 Mon Sep 17 00:00:00 2001
+From b3021cdc4b4c2cf547c5bc2d1d21a5a00ffea001 Mon Sep 17 00:00:00 2001
 From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
 Date: Mon, 26 Sep 2022 12:55:07 -0700
 Subject: [PATCH] Remove use of LiteralString in builtins (#13743)
 
 ---
- mypy/typeshed/stdlib/builtins.pyi | 100 +-----------------------------
- 1 file changed, 1 insertion(+), 99 deletions(-)
+ mypy/typeshed/stdlib/builtins.pyi | 98 -------------------------------
+ 1 file changed, 98 deletions(-)
 
 diff --git a/mypy/typeshed/stdlib/builtins.pyi b/mypy/typeshed/stdlib/builtins.pyi
-index 693dd0b77..8acdeadff 100644
+index efc51fe25..8600a372b 100644
 --- a/mypy/typeshed/stdlib/builtins.pyi
 +++ b/mypy/typeshed/stdlib/builtins.pyi
 @@ -64,7 +64,6 @@ from typing import (  # noqa: Y022,UP035
@@ -163,10 +163,9 @@ index 693dd0b77..8acdeadff 100644
      def __eq__(self, value: object, /) -> bool: ...
      def __ge__(self, value: str, /) -> bool: ...
 -    @overload
--    def __getitem__(self: LiteralString, key: SupportsIndex | slice, /) -> LiteralString: ...
+-    def __getitem__(self: LiteralString, key: SupportsIndex | slice[SupportsIndex | None], /) -> LiteralString: ...
 -    @overload
--    def __getitem__(self, key: SupportsIndex | slice, /) -> str: ...  # type: ignore[misc]
-+    def __getitem__(self, key: SupportsIndex | slice, /) -> str: ...
+     def __getitem__(self, key: SupportsIndex | slice[SupportsIndex | None], /) -> str: ...  # type: ignore[misc]
      def __gt__(self, value: str, /) -> bool: ...
      def __hash__(self) -> int: ...
 -    @overload
diff --git a/mypy/server/aststrip.py b/mypy/server/aststrip.py
index cf706e97c3da7..3e91de8d33a15 100644
--- a/mypy/server/aststrip.py
+++ b/mypy/server/aststrip.py
@@ -136,9 +136,7 @@ def visit_class_def(self, node: ClassDef) -> None:
         node.type_vars = []
         node.base_type_exprs.extend(node.removed_base_type_exprs)
         node.removed_base_type_exprs = []
-        node.defs.body = [
-            s for s in node.defs.body if s not in to_delete  # type: ignore[comparison-overlap]
-        ]
+        node.defs.body = [s for s in node.defs.body if s not in to_delete]
         with self.enter_class(node.info):
             super().visit_class_def(node)
         node.defs.body.extend(node.removed_statements)
diff --git a/mypy/typeshed/stdlib/VERSIONS b/mypy/typeshed/stdlib/VERSIONS
index 6fcf0161790d6..e26bb8da2574e 100644
--- a/mypy/typeshed/stdlib/VERSIONS
+++ b/mypy/typeshed/stdlib/VERSIONS
@@ -253,6 +253,7 @@ py_compile: 3.0-
 pyclbr: 3.0-
 pydoc: 3.0-
 pydoc_data: 3.0-
+pydoc_data.module_docs: 3.13-
 pyexpat: 3.0-
 queue: 3.0-
 quopri: 3.0-
diff --git a/mypy/typeshed/stdlib/_collections_abc.pyi b/mypy/typeshed/stdlib/_collections_abc.pyi
index 319577c9284bc..0fa81662dfbc1 100644
--- a/mypy/typeshed/stdlib/_collections_abc.pyi
+++ b/mypy/typeshed/stdlib/_collections_abc.pyi
@@ -1,7 +1,7 @@
 import sys
 from abc import abstractmethod
 from types import MappingProxyType
-from typing import (  # noqa: Y022,Y038,UP035,Y057
+from typing import (  # noqa: Y022,Y038,UP035,Y057,RUF100
     AbstractSet as Set,
     AsyncGenerator as AsyncGenerator,
     AsyncIterable as AsyncIterable,
diff --git a/mypy/typeshed/stdlib/_ctypes.pyi b/mypy/typeshed/stdlib/_ctypes.pyi
index b7a3fb104596d..0e02092a361c9 100644
--- a/mypy/typeshed/stdlib/_ctypes.pyi
+++ b/mypy/typeshed/stdlib/_ctypes.pyi
@@ -6,7 +6,7 @@ from abc import abstractmethod
 from collections.abc import Callable, Iterable, Iterator, Mapping, Sequence
 from ctypes import CDLL, ArgumentError as ArgumentError, c_void_p
 from types import GenericAlias
-from typing import Any, ClassVar, Final, Generic, Literal, TypeVar, final, overload, type_check_only
+from typing import Any, ClassVar, Final, Generic, Literal, SupportsIndex, TypeVar, final, overload, type_check_only
 from typing_extensions import Self, TypeAlias
 
 _T = TypeVar("_T")
@@ -134,7 +134,7 @@ class _Pointer(_PointerLike, _CData, Generic[_CT], metaclass=_PyCPointerType):
     @overload
     def __getitem__(self, key: int, /) -> Any: ...
     @overload
-    def __getitem__(self, key: slice, /) -> list[Any]: ...
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> list[Any]: ...
     def __setitem__(self, key: int, value: Any, /) -> None: ...
 
 if sys.version_info < (3, 14):
@@ -338,11 +338,11 @@ class Array(_CData, Generic[_CT], metaclass=_PyCArrayType):
     @overload
     def __getitem__(self, key: int, /) -> Any: ...
     @overload
-    def __getitem__(self, key: slice, /) -> list[Any]: ...
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> list[Any]: ...
     @overload
     def __setitem__(self, key: int, value: Any, /) -> None: ...
     @overload
-    def __setitem__(self, key: slice, value: Iterable[Any], /) -> None: ...
+    def __setitem__(self, key: slice[SupportsIndex | None], value: Iterable[Any], /) -> None: ...
     def __iter__(self) -> Iterator[Any]: ...
     # Can't inherit from Sized because the metaclass conflict between
     # Sized and _CData prevents using _CDataMeta.
diff --git a/mypy/typeshed/stdlib/_operator.pyi b/mypy/typeshed/stdlib/_operator.pyi
index cb1c1bcfc4aab..e1ef5c4bf0678 100644
--- a/mypy/typeshed/stdlib/_operator.pyi
+++ b/mypy/typeshed/stdlib/_operator.pyi
@@ -80,20 +80,20 @@ def concat(a: Sequence[_T], b: Sequence[_T], /) -> Sequence[_T]: ...
 def contains(a: Container[object], b: object, /) -> bool: ...
 def countOf(a: Iterable[object], b: object, /) -> int: ...
 @overload
-def delitem(a: MutableSequence[Any], b: SupportsIndex, /) -> None: ...
+def delitem(a: MutableSequence[Any], b: int, /) -> None: ...
 @overload
-def delitem(a: MutableSequence[Any], b: slice, /) -> None: ...
+def delitem(a: MutableSequence[Any], b: slice[int | None], /) -> None: ...
 @overload
 def delitem(a: MutableMapping[_K, Any], b: _K, /) -> None: ...
 @overload
-def getitem(a: Sequence[_T], b: slice, /) -> Sequence[_T]: ...
+def getitem(a: Sequence[_T], b: slice[int | None], /) -> Sequence[_T]: ...
 @overload
 def getitem(a: SupportsGetItem[_K, _V], b: _K, /) -> _V: ...
 def indexOf(a: Iterable[_T], b: _T, /) -> int: ...
 @overload
-def setitem(a: MutableSequence[_T], b: SupportsIndex, c: _T, /) -> None: ...
+def setitem(a: MutableSequence[_T], b: int, c: _T, /) -> None: ...
 @overload
-def setitem(a: MutableSequence[_T], b: slice, c: Sequence[_T], /) -> None: ...
+def setitem(a: MutableSequence[_T], b: slice[int | None], c: Sequence[_T], /) -> None: ...
 @overload
 def setitem(a: MutableMapping[_K, _V], b: _K, c: _V, /) -> None: ...
 def length_hint(obj: object, default: int = 0, /) -> int: ...
diff --git a/mypy/typeshed/stdlib/_socket.pyi b/mypy/typeshed/stdlib/_socket.pyi
index cdad886b3415e..372b35f22f175 100644
--- a/mypy/typeshed/stdlib/_socket.pyi
+++ b/mypy/typeshed/stdlib/_socket.pyi
@@ -587,7 +587,7 @@ if sys.platform != "linux":
 
 has_ipv6: bool
 
-if sys.platform != "darwin" and sys.platform != "linux":
+if sys.platform != "darwin":
     BDADDR_ANY: Final = "00:00:00:00:00:00"
     BDADDR_LOCAL: Final = "00:00:00:FF:FF:FF"
 
@@ -660,16 +660,16 @@ if sys.platform == "darwin":
     PF_SYSTEM: Final[int]
     SYSPROTO_CONTROL: Final[int]
 
-if sys.platform != "darwin" and sys.platform != "linux":
+if sys.platform != "darwin":
     AF_BLUETOOTH: Final[int]
 
-if sys.platform != "win32" and sys.platform != "darwin" and sys.platform != "linux":
+if sys.platform != "win32" and sys.platform != "darwin":
     # Linux and some BSD support is explicit in the docs
     # Windows and macOS do not support in practice
     BTPROTO_HCI: Final[int]
     BTPROTO_L2CAP: Final[int]
     BTPROTO_SCO: Final[int]  # not in FreeBSD
-if sys.platform != "darwin" and sys.platform != "linux":
+if sys.platform != "darwin":
     BTPROTO_RFCOMM: Final[int]
 
 if sys.platform == "linux":
diff --git a/mypy/typeshed/stdlib/_thread.pyi b/mypy/typeshed/stdlib/_thread.pyi
index 6969ae48cae79..1323a55e9aad8 100644
--- a/mypy/typeshed/stdlib/_thread.pyi
+++ b/mypy/typeshed/stdlib/_thread.pyi
@@ -5,7 +5,7 @@ from collections.abc import Callable
 from threading import Thread
 from types import TracebackType
 from typing import Any, Final, NoReturn, final, overload
-from typing_extensions import TypeVarTuple, Unpack, disjoint_base
+from typing_extensions import TypeVarTuple, Unpack, deprecated, disjoint_base
 
 _Ts = TypeVarTuple("_Ts")
 
@@ -38,9 +38,12 @@ if sys.version_info >= (3, 13):
         def acquire(self, blocking: bool = True, timeout: float = -1) -> bool: ...
         def release(self) -> None: ...
         def locked(self) -> bool: ...
-        def acquire_lock(self, blocking: bool = True, timeout: float = -1) -> bool: ...
-        def release_lock(self) -> None: ...
-        def locked_lock(self) -> bool: ...
+        @deprecated("Obsolete synonym. Use `acquire()` instead.")
+        def acquire_lock(self, blocking: bool = True, timeout: float = -1) -> bool: ...  # undocumented
+        @deprecated("Obsolete synonym. Use `release()` instead.")
+        def release_lock(self) -> None: ...  # undocumented
+        @deprecated("Obsolete synonym. Use `locked()` instead.")
+        def locked_lock(self) -> bool: ...  # undocumented
         def __enter__(self) -> bool: ...
         def __exit__(
             self, type: type[BaseException] | None, value: BaseException | None, traceback: TracebackType | None
@@ -53,9 +56,12 @@ else:
         def acquire(self, blocking: bool = True, timeout: float = -1) -> bool: ...
         def release(self) -> None: ...
         def locked(self) -> bool: ...
-        def acquire_lock(self, blocking: bool = True, timeout: float = -1) -> bool: ...
-        def release_lock(self) -> None: ...
-        def locked_lock(self) -> bool: ...
+        @deprecated("Obsolete synonym. Use `acquire()` instead.")
+        def acquire_lock(self, blocking: bool = True, timeout: float = -1) -> bool: ...  # undocumented
+        @deprecated("Obsolete synonym. Use `release()` instead.")
+        def release_lock(self) -> None: ...  # undocumented
+        @deprecated("Obsolete synonym. Use `locked()` instead.")
+        def locked_lock(self) -> bool: ...  # undocumented
         def __enter__(self) -> bool: ...
         def __exit__(
             self, type: type[BaseException] | None, value: BaseException | None, traceback: TracebackType | None
@@ -65,12 +71,12 @@ else:
 def start_new_thread(function: Callable[[Unpack[_Ts]], object], args: tuple[Unpack[_Ts]], /) -> int: ...
 @overload
 def start_new_thread(function: Callable[..., object], args: tuple[Any, ...], kwargs: dict[str, Any], /) -> int: ...
-
-# Obsolete synonym for start_new_thread()
 @overload
-def start_new(function: Callable[[Unpack[_Ts]], object], args: tuple[Unpack[_Ts]], /) -> int: ...
+@deprecated("Obsolete synonym. Use `start_new_thread()` instead.")
+def start_new(function: Callable[[Unpack[_Ts]], object], args: tuple[Unpack[_Ts]], /) -> int: ...  # undocumented
 @overload
-def start_new(function: Callable[..., object], args: tuple[Any, ...], kwargs: dict[str, Any], /) -> int: ...
+@deprecated("Obsolete synonym. Use `start_new_thread()` instead.")
+def start_new(function: Callable[..., object], args: tuple[Any, ...], kwargs: dict[str, Any], /) -> int: ...  # undocumented
 
 if sys.version_info >= (3, 10):
     def interrupt_main(signum: signal.Signals = signal.SIGINT, /) -> None: ...
@@ -79,9 +85,11 @@ else:
     def interrupt_main() -> None: ...
 
 def exit() -> NoReturn: ...
-def exit_thread() -> NoReturn: ...  # Obsolete synonym for exit()
+@deprecated("Obsolete synonym. Use `exit()` instead.")
+def exit_thread() -> NoReturn: ...  # undocumented
 def allocate_lock() -> LockType: ...
-def allocate() -> LockType: ...  # Obsolete synonym for allocate_lock()
+@deprecated("Obsolete synonym. Use `allocate_lock()` instead.")
+def allocate() -> LockType: ...  # undocumented
 def get_ident() -> int: ...
 def stack_size(size: int = 0, /) -> int: ...
 
diff --git a/mypy/typeshed/stdlib/_typeshed/README.md b/mypy/typeshed/stdlib/_typeshed/README.md
index f4808944fa7bd..3e4f3cb5cd48c 100644
--- a/mypy/typeshed/stdlib/_typeshed/README.md
+++ b/mypy/typeshed/stdlib/_typeshed/README.md
@@ -1,6 +1,6 @@
 # Utility types for typeshed
 
-This package and its submodules contains various common types used by
+This package and its submodules contain various common types used by
 typeshed. It can also be used by packages outside typeshed, but beware
 the API stability guarantees below.
 
diff --git a/mypy/typeshed/stdlib/_typeshed/__init__.pyi b/mypy/typeshed/stdlib/_typeshed/__init__.pyi
index b786923880e13..89e93ab027069 100644
--- a/mypy/typeshed/stdlib/_typeshed/__init__.pyi
+++ b/mypy/typeshed/stdlib/_typeshed/__init__.pyi
@@ -300,7 +300,7 @@ WriteableBuffer: TypeAlias = Buffer
 ReadableBuffer: TypeAlias = Buffer  # stable
 
 class SliceableBuffer(Buffer, Protocol):
-    def __getitem__(self, slice: slice, /) -> Sequence[int]: ...
+    def __getitem__(self, slice: slice[SupportsIndex | None], /) -> Sequence[int]: ...
 
 class IndexableBuffer(Buffer, Protocol):
     def __getitem__(self, i: int, /) -> int: ...
@@ -308,7 +308,7 @@ class IndexableBuffer(Buffer, Protocol):
 class SupportsGetItemBuffer(SliceableBuffer, IndexableBuffer, Protocol):
     def __contains__(self, x: Any, /) -> bool: ...
     @overload
-    def __getitem__(self, slice: slice, /) -> Sequence[int]: ...
+    def __getitem__(self, slice: slice[SupportsIndex | None], /) -> Sequence[int]: ...
     @overload
     def __getitem__(self, i: int, /) -> int: ...
 
diff --git a/mypy/typeshed/stdlib/argparse.pyi b/mypy/typeshed/stdlib/argparse.pyi
index c87b8f4fcc4c4..c2a6f36911968 100644
--- a/mypy/typeshed/stdlib/argparse.pyi
+++ b/mypy/typeshed/stdlib/argparse.pyi
@@ -336,7 +336,10 @@ class HelpFormatter:
     def _format_usage(
         self, usage: str | None, actions: Iterable[Action], groups: Iterable[_MutuallyExclusiveGroup], prefix: str | None
     ) -> str: ...
-    def _format_actions_usage(self, actions: Iterable[Action], groups: Iterable[_MutuallyExclusiveGroup]) -> str: ...
+    if sys.version_info < (3, 14):
+        # Removed in Python 3.14.3
+        def _format_actions_usage(self, actions: Iterable[Action], groups: Iterable[_MutuallyExclusiveGroup]) -> str: ...
+
     def _format_text(self, text: str) -> str: ...
     def _format_action(self, action: Action) -> str: ...
     def _format_action_invocation(self, action: Action) -> str: ...
diff --git a/mypy/typeshed/stdlib/array.pyi b/mypy/typeshed/stdlib/array.pyi
index a6b0344a1e2ea..eb679dd50f722 100644
--- a/mypy/typeshed/stdlib/array.pyi
+++ b/mypy/typeshed/stdlib/array.pyi
@@ -80,12 +80,12 @@ class array(MutableSequence[_T]):
     @overload
     def __getitem__(self, key: SupportsIndex, /) -> _T: ...
     @overload
-    def __getitem__(self, key: slice, /) -> array[_T]: ...
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> array[_T]: ...
     @overload  # type: ignore[override]
     def __setitem__(self, key: SupportsIndex, value: _T, /) -> None: ...
     @overload
-    def __setitem__(self, key: slice, value: array[_T], /) -> None: ...
-    def __delitem__(self, key: SupportsIndex | slice, /) -> None: ...
+    def __setitem__(self, key: slice[SupportsIndex | None], value: array[_T], /) -> None: ...
+    def __delitem__(self, key: SupportsIndex | slice[SupportsIndex | None], /) -> None: ...
     def __add__(self, value: array[_T], /) -> array[_T]: ...
     def __eq__(self, value: object, /) -> bool: ...
     def __ge__(self, value: array[_T], /) -> bool: ...
diff --git a/mypy/typeshed/stdlib/builtins.pyi b/mypy/typeshed/stdlib/builtins.pyi
index 0f2196070de20..03c3bd2e17c74 100644
--- a/mypy/typeshed/stdlib/builtins.pyi
+++ b/mypy/typeshed/stdlib/builtins.pyi
@@ -37,7 +37,7 @@ from types import CellType, CodeType, GenericAlias, TracebackType
 
 # mypy crashes if any of {ByteString, Sequence, MutableSequence, Mapping, MutableMapping}
 # are imported from collections.abc in builtins.pyi
-from typing import (  # noqa: Y022,UP035
+from typing import (  # noqa: Y022,UP035,RUF100
     IO,
     Any,
     BinaryIO,
@@ -549,7 +549,7 @@ class str(Sequence[str]):
     def __contains__(self, key: str, /) -> bool: ...  # type: ignore[override]
     def __eq__(self, value: object, /) -> bool: ...
     def __ge__(self, value: str, /) -> bool: ...
-    def __getitem__(self, key: SupportsIndex | slice, /) -> str: ...
+    def __getitem__(self, key: SupportsIndex | slice[SupportsIndex | None], /) -> str: ...  # type: ignore[misc]
     def __gt__(self, value: str, /) -> bool: ...
     def __hash__(self) -> int: ...
     def __iter__(self) -> Iterator[str]: ...  # type: ignore[misc]
@@ -648,7 +648,7 @@ class bytes(Sequence[int]):
     @overload
     def __getitem__(self, key: SupportsIndex, /) -> int: ...
     @overload
-    def __getitem__(self, key: slice, /) -> bytes: ...
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> bytes: ...
     def __add__(self, value: ReadableBuffer, /) -> bytes: ...
     def __mul__(self, value: SupportsIndex, /) -> bytes: ...
     def __rmul__(self, value: SupportsIndex, /) -> bytes: ...
@@ -758,12 +758,12 @@ class bytearray(MutableSequence[int]):
     @overload
     def __getitem__(self, key: SupportsIndex, /) -> int: ...
     @overload
-    def __getitem__(self, key: slice, /) -> bytearray: ...
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> bytearray: ...
     @overload
     def __setitem__(self, key: SupportsIndex, value: SupportsIndex, /) -> None: ...
     @overload
-    def __setitem__(self, key: slice, value: Iterable[SupportsIndex] | bytes, /) -> None: ...
-    def __delitem__(self, key: SupportsIndex | slice, /) -> None: ...
+    def __setitem__(self, key: slice[SupportsIndex | None], value: Iterable[SupportsIndex] | bytes, /) -> None: ...
+    def __delitem__(self, key: SupportsIndex | slice[SupportsIndex | None], /) -> None: ...
     def __add__(self, value: ReadableBuffer, /) -> bytearray: ...
     # The superclass wants us to accept Iterable[int], but that fails at runtime.
     def __iadd__(self, value: ReadableBuffer, /) -> Self: ...  # type: ignore[override]
@@ -835,14 +835,14 @@ class memoryview(Sequence[_I]):
     @overload
     def __getitem__(self, key: SupportsIndex | tuple[SupportsIndex, ...], /) -> _I: ...
     @overload
-    def __getitem__(self, key: slice, /) -> memoryview[_I]: ...
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> memoryview[_I]: ...
     def __contains__(self, x: object, /) -> bool: ...
     def __iter__(self) -> Iterator[_I]: ...
     def __len__(self) -> int: ...
     def __eq__(self, value: object, /) -> bool: ...
     def __hash__(self) -> int: ...
     @overload
-    def __setitem__(self, key: slice, value: ReadableBuffer, /) -> None: ...
+    def __setitem__(self, key: slice[SupportsIndex | None], value: ReadableBuffer, /) -> None: ...
     @overload
     def __setitem__(self, key: SupportsIndex | tuple[SupportsIndex, ...], value: _I, /) -> None: ...
     if sys.version_info >= (3, 10):
@@ -949,7 +949,7 @@ class tuple(Sequence[_T_co]):
     @overload
     def __getitem__(self, key: SupportsIndex, /) -> _T_co: ...
     @overload
-    def __getitem__(self, key: slice, /) -> tuple[_T_co, ...]: ...
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> tuple[_T_co, ...]: ...
     def __iter__(self) -> Iterator[_T_co]: ...
     def __lt__(self, value: tuple[_T_co, ...], /) -> bool: ...
     def __le__(self, value: tuple[_T_co, ...], /) -> bool: ...
@@ -1049,12 +1049,12 @@ class list(MutableSequence[_T]):
     @overload
     def __getitem__(self, i: SupportsIndex, /) -> _T: ...
     @overload
-    def __getitem__(self, s: slice, /) -> list[_T]: ...
+    def __getitem__(self, s: slice[SupportsIndex | None], /) -> list[_T]: ...
     @overload
     def __setitem__(self, key: SupportsIndex, value: _T, /) -> None: ...
     @overload
-    def __setitem__(self, key: slice, value: Iterable[_T], /) -> None: ...
-    def __delitem__(self, key: SupportsIndex | slice, /) -> None: ...
+    def __setitem__(self, key: slice[SupportsIndex | None], value: Iterable[_T], /) -> None: ...
+    def __delitem__(self, key: SupportsIndex | slice[SupportsIndex | None], /) -> None: ...
     # Overloading looks unnecessary, but is needed to work around complex mypy problems
     @overload
     def __add__(self, value: list[_T], /) -> list[_T]: ...
@@ -1254,7 +1254,7 @@ class range(Sequence[int]):
     @overload
     def __getitem__(self, key: SupportsIndex, /) -> int: ...
     @overload
-    def __getitem__(self, key: slice, /) -> range: ...
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> range: ...
     def __reversed__(self) -> Iterator[int]: ...
 
 @disjoint_base
@@ -1287,10 +1287,10 @@ def abs(x: SupportsAbs[_T], /) -> _T: ...
 def all(iterable: Iterable[object], /) -> bool: ...
 def any(iterable: Iterable[object], /) -> bool: ...
 def ascii(obj: object, /) -> str: ...
-def bin(number: int | SupportsIndex, /) -> str: ...
+def bin(number: SupportsIndex, /) -> str: ...
 def breakpoint(*args: Any, **kws: Any) -> None: ...
 def callable(obj: object, /) -> TypeIs[Callable[..., object]]: ...
-def chr(i: int | SupportsIndex, /) -> str: ...
+def chr(i: SupportsIndex, /) -> str: ...
 
 if sys.version_info >= (3, 10):
     def aiter(async_iterable: SupportsAiter[_SupportsAnextT_co], /) -> _SupportsAnextT_co: ...
@@ -1448,7 +1448,7 @@ def hash(obj: object, /) -> int: ...
 
 help: _sitebuiltins._Helper
 
-def hex(number: int | SupportsIndex, /) -> str: ...
+def hex(number: SupportsIndex, /) -> str: ...
 def id(obj: object, /) -> int: ...
 def input(prompt: object = "", /) -> str: ...
 @type_check_only
@@ -1615,7 +1615,7 @@ def min(iterable: Iterable[_T1], /, *, key: Callable[[_T1], SupportsRichComparis
 def next(i: SupportsNext[_T], /) -> _T: ...
 @overload
 def next(i: SupportsNext[_T], default: _VT, /) -> _T | _VT: ...
-def oct(number: int | SupportsIndex, /) -> str: ...
+def oct(number: SupportsIndex, /) -> str: ...
 
 _Opener: TypeAlias = Callable[[str, int], int]
 
diff --git a/mypy/typeshed/stdlib/collections/__init__.pyi b/mypy/typeshed/stdlib/collections/__init__.pyi
index 8636e6cdbdc31..95f13b0c8dd2b 100644
--- a/mypy/typeshed/stdlib/collections/__init__.pyi
+++ b/mypy/typeshed/stdlib/collections/__init__.pyi
@@ -129,12 +129,12 @@ class UserList(MutableSequence[_T]):
     @overload
     def __getitem__(self, i: SupportsIndex) -> _T: ...
     @overload
-    def __getitem__(self, i: slice) -> Self: ...
+    def __getitem__(self, i: slice[SupportsIndex | None]) -> Self: ...
     @overload
     def __setitem__(self, i: SupportsIndex, item: _T) -> None: ...
     @overload
-    def __setitem__(self, i: slice, item: Iterable[_T]) -> None: ...
-    def __delitem__(self, i: SupportsIndex | slice) -> None: ...
+    def __setitem__(self, i: slice[SupportsIndex | None], item: Iterable[_T]) -> None: ...
+    def __delitem__(self, i: SupportsIndex | slice[SupportsIndex | None]) -> None: ...
     def __add__(self, other: Iterable[_T]) -> Self: ...
     def __radd__(self, other: Iterable[_T]) -> Self: ...
     def __iadd__(self, other: Iterable[_T]) -> Self: ...
@@ -174,7 +174,7 @@ class UserString(Sequence[UserString]):
     def __hash__(self) -> int: ...
     def __contains__(self, char: object) -> bool: ...
     def __len__(self) -> int: ...
-    def __getitem__(self, index: SupportsIndex | slice) -> Self: ...
+    def __getitem__(self, index: SupportsIndex | slice[SupportsIndex | None]) -> Self: ...
     def __iter__(self) -> Iterator[Self]: ...
     def __reversed__(self) -> Iterator[Self]: ...
     def __add__(self, other: object) -> Self: ...
diff --git a/mypy/typeshed/stdlib/contextlib.pyi b/mypy/typeshed/stdlib/contextlib.pyi
index 221102ee23956..8d5902c469120 100644
--- a/mypy/typeshed/stdlib/contextlib.pyi
+++ b/mypy/typeshed/stdlib/contextlib.pyi
@@ -5,7 +5,7 @@ from abc import ABC, abstractmethod
 from collections.abc import AsyncGenerator, AsyncIterator, Awaitable, Callable, Generator, Iterator
 from types import TracebackType
 from typing import Any, Generic, Protocol, TypeVar, overload, runtime_checkable, type_check_only
-from typing_extensions import ParamSpec, Self, TypeAlias
+from typing_extensions import ParamSpec, Self, TypeAlias, deprecated
 
 __all__ = [
     "contextmanager",
@@ -86,6 +86,12 @@ class _GeneratorContextManager(
         self, typ: type[BaseException] | None, value: BaseException | None, traceback: TracebackType | None
     ) -> bool | None: ...
 
+@overload
+def contextmanager(func: Callable[_P, Generator[_T_co, None, object]]) -> Callable[_P, _GeneratorContextManager[_T_co]]: ...
+@overload
+@deprecated(
+    "Annotating the return type as `-> Iterator[Foo]` with `@contextmanager` is deprecated. Use `-> Generator[Foo]` instead."
+)
 def contextmanager(func: Callable[_P, Iterator[_T_co]]) -> Callable[_P, _GeneratorContextManager[_T_co]]: ...
 
 if sys.version_info >= (3, 10):
@@ -112,6 +118,13 @@ else:
             self, typ: type[BaseException] | None, value: BaseException | None, traceback: TracebackType | None
         ) -> bool | None: ...
 
+@overload
+def asynccontextmanager(func: Callable[_P, AsyncGenerator[_T_co]]) -> Callable[_P, _AsyncGeneratorContextManager[_T_co]]: ...
+@overload
+@deprecated(
+    "Annotating the return type as `-> AsyncIterator[Foo]` with `@asynccontextmanager` is deprecated. "
+    "Use `-> AsyncGenerator[Foo]` instead."
+)
 def asynccontextmanager(func: Callable[_P, AsyncIterator[_T_co]]) -> Callable[_P, _AsyncGeneratorContextManager[_T_co]]: ...
 @type_check_only
 class _SupportsClose(Protocol):
diff --git a/mypy/typeshed/stdlib/email/_header_value_parser.pyi b/mypy/typeshed/stdlib/email/_header_value_parser.pyi
index dededd006e5b5..32caf83bd0220 100644
--- a/mypy/typeshed/stdlib/email/_header_value_parser.pyi
+++ b/mypy/typeshed/stdlib/email/_header_value_parser.pyi
@@ -1,3 +1,4 @@
+import sys
 from collections.abc import Iterable, Iterator
 from email.errors import HeaderParseError, MessageDefect
 from email.policy import Policy
@@ -25,6 +26,10 @@ SPECIALSNL: Final[set[str]]
 def make_quoted_pairs(value: Any) -> str: ...
 def quote_string(value: Any) -> str: ...
 
+if sys.version_info >= (3, 13):
+    # Added in Python 3.13.12, 3.14.3
+    def make_parenthesis_pairs(value: Any) -> str: ...
+
 rfc2047_matcher: Final[Pattern[str]]
 
 class TokenList(list[TokenList | Terminal]):
@@ -311,6 +316,13 @@ class MessageID(MsgID):
 class InvalidMessageID(MessageID):
     token_type: str
 
+if sys.version_info >= (3, 13):
+    # Added in Python 3.13.12, 3.14.3
+    class MessageIDList(TokenList):
+        token_type: str
+        @property
+        def message_ids(self) -> list[MsgID | Terminal]: ...
+
 class Header(TokenList):
     token_type: str
 
@@ -381,6 +393,11 @@ def get_address_list(value: str) -> tuple[AddressList, str]: ...
 def get_no_fold_literal(value: str) -> tuple[NoFoldLiteral, str]: ...
 def get_msg_id(value: str) -> tuple[MsgID, str]: ...
 def parse_message_id(value: str) -> MessageID: ...
+
+if sys.version_info >= (3, 13):
+    # Added in Python 3.13.12, 3.14.3
+    def parse_message_ids(value: str) -> MessageIDList: ...
+
 def parse_mime_version(value: str) -> MIMEVersion: ...
 def get_invalid_parameter(value: str) -> tuple[InvalidParameter, str]: ...
 def get_ttext(value: str) -> tuple[ValueTerminal, str]: ...
diff --git a/mypy/typeshed/stdlib/email/headerregistry.pyi b/mypy/typeshed/stdlib/email/headerregistry.pyi
index bea68307e0091..8033f0ab43560 100644
--- a/mypy/typeshed/stdlib/email/headerregistry.pyi
+++ b/mypy/typeshed/stdlib/email/headerregistry.pyi
@@ -1,3 +1,4 @@
+import sys
 import types
 from collections.abc import Iterable, Mapping
 from datetime import datetime as _datetime
@@ -137,6 +138,17 @@ class MessageIDHeader:
     @staticmethod
     def value_parser(value: str) -> MessageID: ...
 
+if sys.version_info >= (3, 13):
+    from email._header_value_parser import MessageIDList
+
+    # Added in Python 3.13.12, 3.14.3
+    class ReferencesHeader:
+        max_count: ClassVar[Literal[1]]
+        @classmethod
+        def parse(cls, value: str, kwds: dict[str, Any]) -> None: ...
+        @staticmethod
+        def value_parser(value: str) -> MessageIDList: ...
+
 @type_check_only
 class _HeaderParser(Protocol):
     max_count: ClassVar[Literal[1] | None]
diff --git a/mypy/typeshed/stdlib/enum.pyi b/mypy/typeshed/stdlib/enum.pyi
index c6cc5a961ee72..f9b53e1d45f16 100644
--- a/mypy/typeshed/stdlib/enum.pyi
+++ b/mypy/typeshed/stdlib/enum.pyi
@@ -4,7 +4,7 @@ import types
 from _typeshed import SupportsKeysAndGetItem, Unused
 from builtins import property as _builtins_property
 from collections.abc import Callable, Iterable, Iterator, Mapping
-from typing import Any, Final, Generic, Literal, TypeVar, overload
+from typing import Any, Final, Generic, Literal, SupportsIndex, TypeVar, overload
 from typing_extensions import Self, TypeAlias, disjoint_base
 
 __all__ = ["EnumMeta", "Enum", "IntEnum", "Flag", "IntFlag", "auto", "unique"]
@@ -311,6 +311,7 @@ if sys.version_info >= (3, 11):
     def global_enum_repr(self: Enum) -> str: ...
     def global_flag_repr(self: Flag) -> str: ...
     def show_flag_values(value: int) -> list[int]: ...
+    def bin(num: SupportsIndex, max_bits: int | None = None) -> str: ...
 
 if sys.version_info >= (3, 12):
     # The body of the class is the same, but the base classes are different.
diff --git a/mypy/typeshed/stdlib/functools.pyi b/mypy/typeshed/stdlib/functools.pyi
index 52d0d0958134e..57bc3f179f7ac 100644
--- a/mypy/typeshed/stdlib/functools.pyi
+++ b/mypy/typeshed/stdlib/functools.pyi
@@ -63,6 +63,10 @@ class _lru_cache_wrapper(Generic[_T_co]):
     def __copy__(self) -> _lru_cache_wrapper[_T_co]: ...
     def __deepcopy__(self, memo: Any, /) -> _lru_cache_wrapper[_T_co]: ...
 
+    # as with ``Callable``, we'll assume that these attributes exist
+    __name__: str
+    __qualname__: str
+
 @overload
 def lru_cache(maxsize: int | None = 128, typed: bool = False) -> Callable[[Callable[..., _T]], _lru_cache_wrapper[_T]]: ...
 @overload
diff --git a/mypy/typeshed/stdlib/http/cookies.pyi b/mypy/typeshed/stdlib/http/cookies.pyi
index 0373eae8ab297..eadf054c3a5f4 100644
--- a/mypy/typeshed/stdlib/http/cookies.pyi
+++ b/mypy/typeshed/stdlib/http/cookies.pyi
@@ -47,7 +47,7 @@ class Morsel(dict[str, Any], Generic[_T]):
 class BaseCookie(dict[str, Morsel[_T]], Generic[_T]):
     def __init__(self, input: _DataType | None = None) -> None: ...
     def value_decode(self, val: str) -> tuple[_T, str]: ...
-    def value_encode(self, val: _T) -> tuple[_T, str]: ...
+    def value_encode(self, val: _T) -> tuple[str, str]: ...
     def output(self, attrs: list[str] | None = None, header: str = "Set-Cookie:", sep: str = "\r\n") -> str: ...
     __str__ = output
     def js_output(self, attrs: list[str] | None = None) -> str: ...
diff --git a/mypy/typeshed/stdlib/logging/__init__.pyi b/mypy/typeshed/stdlib/logging/__init__.pyi
index 8248f82ea87ac..89c94816a906c 100644
--- a/mypy/typeshed/stdlib/logging/__init__.pyi
+++ b/mypy/typeshed/stdlib/logging/__init__.pyi
@@ -576,19 +576,40 @@ if sys.version_info >= (3, 11):
     def getLevelNamesMapping() -> dict[str, int]: ...
 
 def makeLogRecord(dict: Mapping[str, object]) -> LogRecord: ...
+@overload  # handlers is non-None
 def basicConfig(
     *,
-    filename: StrPath | None = ...,
-    filemode: str = ...,
-    format: str = ...,
-    datefmt: str | None = ...,
-    style: _FormatStyle = ...,
-    level: _Level | None = ...,
-    stream: SupportsWrite[str] | None = ...,
-    handlers: Iterable[Handler] | None = ...,
-    force: bool | None = ...,
-    encoding: str | None = ...,
-    errors: str | None = ...,
+    format: str = ...,  # default value depends on the value of `style`
+    datefmt: str | None = None,
+    style: _FormatStyle = "%",
+    level: _Level | None = None,
+    handlers: Iterable[Handler],
+    force: bool | None = False,
+) -> None: ...
+@overload  # handlers is None, filename is passed (but possibly None)
+def basicConfig(
+    *,
+    filename: StrPath | None,
+    filemode: str = "a",
+    format: str = ...,  # default value depends on the value of `style`
+    datefmt: str | None = None,
+    style: _FormatStyle = "%",
+    level: _Level | None = None,
+    handlers: None = None,
+    force: bool | None = False,
+    encoding: str | None = None,
+    errors: str | None = "backslashreplace",
+) -> None: ...
+@overload  # handlers is None, filename is not passed
+def basicConfig(
+    *,
+    format: str = ...,  # default value depends on the value of `style`
+    datefmt: str | None = None,
+    style: _FormatStyle = "%",
+    level: _Level | None = None,
+    stream: SupportsWrite[str] | None = None,
+    handlers: None = None,
+    force: bool | None = False,
 ) -> None: ...
 def shutdown(handlerList: Sequence[Any] = ...) -> None: ...  # handlerList is undocumented
 def setLoggerClass(klass: type[Logger]) -> None: ...
@@ -616,6 +637,7 @@ class FileHandler(StreamHandler[TextIOWrapper]):
     encoding: str | None  # undocumented
     delay: bool  # undocumented
     errors: str | None  # undocumented
+    stream: TextIOWrapper | None  # type: ignore[assignment]  # None when delay=True or after close()
     def __init__(
         self, filename: StrPath, mode: str = "a", encoding: str | None = None, delay: bool = False, errors: str | None = None
     ) -> None: ...
diff --git a/mypy/typeshed/stdlib/logging/config.pyi b/mypy/typeshed/stdlib/logging/config.pyi
index 72412ddc2cea5..e362145516001 100644
--- a/mypy/typeshed/stdlib/logging/config.pyi
+++ b/mypy/typeshed/stdlib/logging/config.pyi
@@ -97,7 +97,7 @@ class ConvertingList(list[Any], ConvertingMixin):  # undocumented
     @overload
     def __getitem__(self, key: SupportsIndex) -> Any: ...
     @overload
-    def __getitem__(self, key: slice) -> Any: ...
+    def __getitem__(self, key: slice[SupportsIndex | None]) -> Any: ...
     def pop(self, idx: SupportsIndex = -1) -> Any: ...
 
 if sys.version_info >= (3, 12):
@@ -105,7 +105,7 @@ if sys.version_info >= (3, 12):
         @overload
         def __getitem__(self, key: SupportsIndex) -> Any: ...
         @overload
-        def __getitem__(self, key: slice) -> Any: ...
+        def __getitem__(self, key: slice[SupportsIndex | None]) -> Any: ...
 
 else:
     @disjoint_base
@@ -113,7 +113,7 @@ else:
         @overload
         def __getitem__(self, key: SupportsIndex) -> Any: ...
         @overload
-        def __getitem__(self, key: slice) -> Any: ...
+        def __getitem__(self, key: slice[SupportsIndex | None]) -> Any: ...
 
 class BaseConfigurator:
     CONVERT_PATTERN: Pattern[str]
diff --git a/mypy/typeshed/stdlib/mmap.pyi b/mypy/typeshed/stdlib/mmap.pyi
index 98183acba40f8..005020b8b6b30 100644
--- a/mypy/typeshed/stdlib/mmap.pyi
+++ b/mypy/typeshed/stdlib/mmap.pyi
@@ -2,7 +2,7 @@ import os
 import sys
 from _typeshed import ReadableBuffer, Unused
 from collections.abc import Iterator
-from typing import Final, Literal, NoReturn, overload
+from typing import Final, Literal, NoReturn, SupportsIndex, overload
 from typing_extensions import Self, disjoint_base
 
 ACCESS_DEFAULT: Final = 0
@@ -77,14 +77,14 @@ class mmap:
     def read(self, n: int | None = None, /) -> bytes: ...
     def write(self, bytes: ReadableBuffer, /) -> int: ...
     @overload
-    def __getitem__(self, key: int, /) -> int: ...
+    def __getitem__(self, key: SupportsIndex, /) -> int: ...
     @overload
-    def __getitem__(self, key: slice, /) -> bytes: ...
-    def __delitem__(self, key: int | slice, /) -> NoReturn: ...
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> bytes: ...
+    def __delitem__(self, key: SupportsIndex | slice[SupportsIndex | None], /) -> NoReturn: ...
     @overload
-    def __setitem__(self, key: int, value: int, /) -> None: ...
+    def __setitem__(self, key: SupportsIndex, value: int, /) -> None: ...
     @overload
-    def __setitem__(self, key: slice, value: ReadableBuffer, /) -> None: ...
+    def __setitem__(self, key: slice[SupportsIndex | None], value: ReadableBuffer, /) -> None: ...
     # Doesn't actually exist, but the object actually supports "in" because it has __getitem__,
     # so we claim that there is also a __contains__ to help type checkers.
     def __contains__(self, o: object, /) -> bool: ...
diff --git a/mypy/typeshed/stdlib/multiprocessing/forkserver.pyi b/mypy/typeshed/stdlib/multiprocessing/forkserver.pyi
index c4af295d23161..570b492e9daf3 100644
--- a/mypy/typeshed/stdlib/multiprocessing/forkserver.pyi
+++ b/mypy/typeshed/stdlib/multiprocessing/forkserver.pyi
@@ -16,6 +16,7 @@ class ForkServer:
     def ensure_running(self) -> None: ...
 
 if sys.version_info >= (3, 14):
+    # `sys_argv` parameter added in Python 3.14.3
     def main(
         listener_fd: int | None,
         alive_r: FileDescriptorLike,
@@ -23,9 +24,22 @@ if sys.version_info >= (3, 14):
         main_path: str | None = None,
         sys_path: list[str] | None = None,
         *,
+        sys_argv: list[str] | None = None,
         authkey_r: int | None = None,
     ) -> None: ...
 
+elif sys.version_info >= (3, 13):
+    # `sys_argv` parameter added in Python 3.13.12
+    def main(
+        listener_fd: int | None,
+        alive_r: FileDescriptorLike,
+        preload: Sequence[str],
+        main_path: str | None = None,
+        sys_path: list[str] | None = None,
+        *,
+        sys_argv: list[str] | None = None,
+    ) -> None: ...
+
 else:
     def main(
         listener_fd: int | None,
diff --git a/mypy/typeshed/stdlib/multiprocessing/managers.pyi b/mypy/typeshed/stdlib/multiprocessing/managers.pyi
index 87a245b0fa9ca..bc6b2e6a9d27f 100644
--- a/mypy/typeshed/stdlib/multiprocessing/managers.pyi
+++ b/mypy/typeshed/stdlib/multiprocessing/managers.pyi
@@ -172,15 +172,15 @@ class BaseListProxy(BaseProxy, MutableSequence[_T]):
     __builtins__: ClassVar[dict[str, Any]]
     def __len__(self) -> int: ...
     def __add__(self, x: list[_T], /) -> list[_T]: ...
-    def __delitem__(self, i: SupportsIndex | slice, /) -> None: ...
+    def __delitem__(self, i: SupportsIndex | slice[SupportsIndex | None], /) -> None: ...
     @overload
     def __getitem__(self, i: SupportsIndex, /) -> _T: ...
     @overload
-    def __getitem__(self, s: slice, /) -> list[_T]: ...
+    def __getitem__(self, s: slice[SupportsIndex | None], /) -> list[_T]: ...
     @overload
     def __setitem__(self, i: SupportsIndex, o: _T, /) -> None: ...
     @overload
-    def __setitem__(self, s: slice, o: Iterable[_T], /) -> None: ...
+    def __setitem__(self, s: slice[SupportsIndex | None], o: Iterable[_T], /) -> None: ...
     def __mul__(self, n: SupportsIndex, /) -> list[_T]: ...
     def __rmul__(self, n: SupportsIndex, /) -> list[_T]: ...
     def __imul__(self, value: SupportsIndex, /) -> Self: ...
diff --git a/mypy/typeshed/stdlib/multiprocessing/sharedctypes.pyi b/mypy/typeshed/stdlib/multiprocessing/sharedctypes.pyi
index e2ec15f05ea23..f61ca26aab5d6 100644
--- a/mypy/typeshed/stdlib/multiprocessing/sharedctypes.pyi
+++ b/mypy/typeshed/stdlib/multiprocessing/sharedctypes.pyi
@@ -5,7 +5,7 @@ from ctypes import _SimpleCData, c_char
 from multiprocessing.context import BaseContext
 from multiprocessing.synchronize import _LockLike
 from types import TracebackType
-from typing import Any, Generic, Literal, Protocol, TypeVar, overload, type_check_only
+from typing import Any, Generic, Literal, Protocol, SupportsIndex, TypeVar, overload, type_check_only
 
 __all__ = ["RawValue", "RawArray", "Value", "Array", "copy", "synchronized"]
 
@@ -103,27 +103,27 @@ class Synchronized(SynchronizedBase[_SimpleCData[_T]], Generic[_T]):
 class SynchronizedArray(SynchronizedBase[ctypes.Array[_SimpleCData[_T]]], Generic[_T]):
     def __len__(self) -> int: ...
     @overload
-    def __getitem__(self, i: slice) -> list[_T]: ...
+    def __getitem__(self, i: slice[SupportsIndex | None]) -> list[_T]: ...
     @overload
-    def __getitem__(self, i: int) -> _T: ...
+    def __getitem__(self, i: SupportsIndex) -> _T: ...
     @overload
-    def __setitem__(self, i: slice, value: Iterable[_T]) -> None: ...
+    def __setitem__(self, i: slice[SupportsIndex | None], value: Iterable[_T]) -> None: ...
     @overload
-    def __setitem__(self, i: int, value: _T) -> None: ...
-    def __getslice__(self, start: int, stop: int) -> list[_T]: ...
-    def __setslice__(self, start: int, stop: int, values: Iterable[_T]) -> None: ...
+    def __setitem__(self, i: SupportsIndex, value: _T) -> None: ...
+    def __getslice__(self, start: SupportsIndex, stop: SupportsIndex) -> list[_T]: ...
+    def __setslice__(self, start: SupportsIndex, stop: SupportsIndex, values: Iterable[_T]) -> None: ...
 
 class SynchronizedString(SynchronizedArray[bytes]):
     @overload  # type: ignore[override]
-    def __getitem__(self, i: slice) -> bytes: ...
+    def __getitem__(self, i: slice[SupportsIndex | None]) -> bytes: ...
     @overload
-    def __getitem__(self, i: int) -> bytes: ...
+    def __getitem__(self, i: SupportsIndex) -> bytes: ...
     @overload  # type: ignore[override]
-    def __setitem__(self, i: slice, value: bytes) -> None: ...
+    def __setitem__(self, i: slice[SupportsIndex | None], value: bytes) -> None: ...
     @overload
-    def __setitem__(self, i: int, value: bytes) -> None: ...
-    def __getslice__(self, start: int, stop: int) -> bytes: ...  # type: ignore[override]
-    def __setslice__(self, start: int, stop: int, values: bytes) -> None: ...  # type: ignore[override]
+    def __setitem__(self, i: SupportsIndex, value: bytes) -> None: ...
+    def __getslice__(self, start: SupportsIndex, stop: SupportsIndex) -> bytes: ...  # type: ignore[override]
+    def __setslice__(self, start: SupportsIndex, stop: SupportsIndex, values: bytes) -> None: ...  # type: ignore[override]
 
     value: bytes
     raw: bytes
diff --git a/mypy/typeshed/stdlib/pydoc_data/module_docs.pyi b/mypy/typeshed/stdlib/pydoc_data/module_docs.pyi
new file mode 100644
index 0000000000000..e3f716c0b2925
--- /dev/null
+++ b/mypy/typeshed/stdlib/pydoc_data/module_docs.pyi
@@ -0,0 +1,3 @@
+from typing import Final
+
+module_docs: Final[dict[str, str]]
diff --git a/mypy/typeshed/stdlib/socket.pyi b/mypy/typeshed/stdlib/socket.pyi
index 24923192d1a48..a55273a8772c9 100644
--- a/mypy/typeshed/stdlib/socket.pyi
+++ b/mypy/typeshed/stdlib/socket.pyi
@@ -519,9 +519,10 @@ if sys.platform != "win32":
 
         __all__ += ["SO_BINDTODEVICE"]
 
-if sys.platform != "darwin" and sys.platform != "linux":
+if sys.platform != "darwin":
     from _socket import BDADDR_ANY as BDADDR_ANY, BDADDR_LOCAL as BDADDR_LOCAL, BTPROTO_RFCOMM as BTPROTO_RFCOMM
 
+if sys.platform != "darwin" and sys.platform != "linux":
     __all__ += ["BDADDR_ANY", "BDADDR_LOCAL", "BTPROTO_RFCOMM"]
 
 if sys.platform == "darwin" and sys.version_info >= (3, 10):
@@ -969,9 +970,10 @@ if sys.platform != "linux":
 if sys.platform != "darwin" and sys.platform != "linux":
     __all__ += ["AF_BLUETOOTH"]
 
-if sys.platform != "win32" and sys.platform != "darwin" and sys.platform != "linux":
+if sys.platform != "win32" and sys.platform != "darwin":
     from _socket import BTPROTO_HCI as BTPROTO_HCI, BTPROTO_L2CAP as BTPROTO_L2CAP, BTPROTO_SCO as BTPROTO_SCO
 
+if sys.platform != "win32" and sys.platform != "darwin" and sys.platform != "linux":
     __all__ += ["BTPROTO_HCI", "BTPROTO_L2CAP", "BTPROTO_SCO"]
 
 if sys.platform != "win32" and sys.platform != "darwin" and sys.platform != "linux":
@@ -1131,7 +1133,7 @@ class AddressFamily(IntEnum):
         AF_QIPCRTR = 42
     if sys.platform != "linux":
         AF_LINK = 33
-    if sys.platform != "darwin" and sys.platform != "linux":
+    if sys.platform != "darwin":
         AF_BLUETOOTH = 32
     if sys.platform == "win32" and sys.version_info >= (3, 12):
         AF_HYPERV = 34
@@ -1186,7 +1188,7 @@ if sys.platform == "linux":
 
 if sys.platform != "linux":
     AF_LINK: Final = AddressFamily.AF_LINK
-if sys.platform != "darwin" and sys.platform != "linux":
+if sys.platform != "darwin":
     AF_BLUETOOTH: Final = AddressFamily.AF_BLUETOOTH
 if sys.platform == "win32" and sys.version_info >= (3, 12):
     AF_HYPERV: Final = AddressFamily.AF_HYPERV
@@ -1425,7 +1427,7 @@ def getfqdn(name: str = "") -> str: ...
 
 if sys.version_info >= (3, 11):
     def create_connection(
-        address: tuple[str | None, int],
+        address: tuple[str | None, bytes | str | int | None],
         timeout: float | None = ...,
         source_address: _Address | None = None,
         *,
diff --git a/mypy/typeshed/stdlib/sqlite3/__init__.pyi b/mypy/typeshed/stdlib/sqlite3/__init__.pyi
index e4604144f0794..f12f80a35a975 100644
--- a/mypy/typeshed/stdlib/sqlite3/__init__.pyi
+++ b/mypy/typeshed/stdlib/sqlite3/__init__.pyi
@@ -222,7 +222,7 @@ _AdaptedInputData: TypeAlias = _SqliteData | Any
 _Parameters: TypeAlias = SupportsLenAndGetItem[_AdaptedInputData] | Mapping[str, _AdaptedInputData]
 # Controls the legacy transaction handling mode of sqlite3.
 _IsolationLevel: TypeAlias = Literal["DEFERRED", "EXCLUSIVE", "IMMEDIATE"] | None
-_RowFactoryOptions: TypeAlias = type[Row] | Callable[[Cursor, Row], object] | None
+_RowFactoryOptions: TypeAlias = type[Row] | Callable[[Cursor, tuple[Any, ...]], object] | None
 
 @type_check_only
 class _AnyParamWindowAggregateClass(Protocol):
@@ -352,7 +352,7 @@ class Connection:
             self, name: str, num_params: int, aggregate_class: Callable[[], _WindowAggregateClass] | None, /
         ) -> None: ...
 
-    def create_collation(self, name: str, callback: Callable[[str, str], int | SupportsIndex] | None, /) -> None: ...
+    def create_collation(self, name: str, callback: Callable[[str, str], SupportsIndex] | None, /) -> None: ...
     def create_function(
         self, name: str, narg: int, func: Callable[..., _SqliteData] | None, *, deterministic: bool = False
     ) -> None: ...
@@ -443,10 +443,10 @@ class PrepareProtocol:
 class Row(Sequence[Any]):
     def __new__(cls, cursor: Cursor, data: tuple[Any, ...], /) -> Self: ...
     def keys(self) -> list[str]: ...
-    @overload
+    @overload  # Note: really needs int instead of SupportsIndex
     def __getitem__(self, key: int | str, /) -> Any: ...
-    @overload
-    def __getitem__(self, key: slice, /) -> tuple[Any, ...]: ...
+    @overload  # Note: SupportsIndex does work within slices.
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> tuple[Any, ...]: ...
     def __hash__(self) -> int: ...
     def __iter__(self) -> Iterator[Any]: ...
     def __len__(self) -> int: ...
diff --git a/mypy/typeshed/stdlib/tarfile.pyi b/mypy/typeshed/stdlib/tarfile.pyi
index 5eecdd350c0aa..6e68c370f3aa3 100644
--- a/mypy/typeshed/stdlib/tarfile.pyi
+++ b/mypy/typeshed/stdlib/tarfile.pyi
@@ -119,16 +119,16 @@ class TarFile:
     OPEN_METH: ClassVar[Mapping[str, str]]
     name: StrOrBytesPath | None
     mode: Literal["r", "a", "w", "x"]
-    fileobj: _Fileobj | None
-    format: _TarFormat | None
+    fileobj: _Fileobj
+    format: _TarFormat
     tarinfo: type[TarInfo]
-    dereference: bool | None
-    ignore_zeros: bool | None
-    encoding: str | None
+    dereference: bool
+    ignore_zeros: bool
+    encoding: str
     errors: str
     fileobject: type[ExFileObject]  # undocumented
     pax_headers: Mapping[str, str]
-    debug: int | None
+    debug: int
     errorlevel: int
     offset: int  # undocumented
     extraction_filter: _FilterFunction | None
diff --git a/mypy/typeshed/stdlib/time.pyi b/mypy/typeshed/stdlib/time.pyi
index 5665efbba69d0..d0853792b636d 100644
--- a/mypy/typeshed/stdlib/time.pyi
+++ b/mypy/typeshed/stdlib/time.pyi
@@ -1,10 +1,17 @@
 import sys
 from _typeshed import structseq
-from typing import Any, Final, Literal, Protocol, final, type_check_only
+from typing import Any, Final, Literal, Protocol, SupportsFloat, SupportsIndex, Union, final, type_check_only
 from typing_extensions import TypeAlias
 
 _TimeTuple: TypeAlias = tuple[int, int, int, int, int, int, int, int, int]
 
+if sys.version_info >= (3, 15):
+    # anticipate on https://github.com/python/cpython/pull/139224
+    _SupportsFloatOrIndex: TypeAlias = Union[SupportsFloat, SupportsIndex]
+else:
+    # before, time functions only accept (subclass of) float, *not* SupportsFloat
+    _SupportsFloatOrIndex: TypeAlias = Union[float, SupportsIndex]
+
 altzone: int
 daylight: int
 timezone: int
@@ -68,11 +75,11 @@ class struct_time(structseq[Any | int], _TimeTuple):
     def tm_gmtoff(self) -> int: ...
 
 def asctime(time_tuple: _TimeTuple | struct_time = ..., /) -> str: ...
-def ctime(seconds: float | None = None, /) -> str: ...
-def gmtime(seconds: float | None = None, /) -> struct_time: ...
-def localtime(seconds: float | None = None, /) -> struct_time: ...
+def ctime(seconds: _SupportsFloatOrIndex | None = None, /) -> str: ...
+def gmtime(seconds: _SupportsFloatOrIndex | None = None, /) -> struct_time: ...
+def localtime(seconds: _SupportsFloatOrIndex | None = None, /) -> struct_time: ...
 def mktime(time_tuple: _TimeTuple | struct_time, /) -> float: ...
-def sleep(seconds: float, /) -> None: ...
+def sleep(seconds: _SupportsFloatOrIndex, /) -> None: ...
 def strftime(format: str, time_tuple: _TimeTuple | struct_time = ..., /) -> str: ...
 def strptime(data_string: str, format: str = "%a %b %d %H:%M:%S %Y", /) -> struct_time: ...
 def time() -> float: ...
diff --git a/mypy/typeshed/stdlib/traceback.pyi b/mypy/typeshed/stdlib/traceback.pyi
index d587295cd1cf7..4305706afa20b 100644
--- a/mypy/typeshed/stdlib/traceback.pyi
+++ b/mypy/typeshed/stdlib/traceback.pyi
@@ -2,7 +2,7 @@ import sys
 from _typeshed import SupportsWrite, Unused
 from collections.abc import Generator, Iterable, Iterator, Mapping
 from types import FrameType, TracebackType
-from typing import Any, ClassVar, Literal, overload
+from typing import Any, ClassVar, Literal, SupportsIndex, overload
 from typing_extensions import Self, TypeAlias, deprecated
 
 __all__ = [
@@ -305,9 +305,9 @@ class FrameSummary:
     @overload
     def __getitem__(self, pos: Literal[3]) -> str | None: ...
     @overload
-    def __getitem__(self, pos: int) -> Any: ...
+    def __getitem__(self, pos: SupportsIndex) -> Any: ...
     @overload
-    def __getitem__(self, pos: slice) -> tuple[Any, ...]: ...
+    def __getitem__(self, pos: slice[SupportsIndex | None]) -> tuple[Any, ...]: ...
     def __iter__(self) -> Iterator[Any]: ...
     def __eq__(self, other: object) -> bool: ...
     def __len__(self) -> Literal[4]: ...
diff --git a/mypy/typeshed/stdlib/tracemalloc.pyi b/mypy/typeshed/stdlib/tracemalloc.pyi
index 31d8f74456395..2a7ee0051af9c 100644
--- a/mypy/typeshed/stdlib/tracemalloc.pyi
+++ b/mypy/typeshed/stdlib/tracemalloc.pyi
@@ -95,7 +95,7 @@ class Traceback(Sequence[Frame]):
     @overload
     def __getitem__(self, index: SupportsIndex) -> Frame: ...
     @overload
-    def __getitem__(self, index: slice) -> Sequence[Frame]: ...
+    def __getitem__(self, index: slice[SupportsIndex | None]) -> Sequence[Frame]: ...
     def __contains__(self, frame: Frame) -> bool: ...  # type: ignore[override]
     def __len__(self) -> int: ...
     def __eq__(self, other: object) -> bool: ...
diff --git a/mypy/typeshed/stdlib/typing.pyi b/mypy/typeshed/stdlib/typing.pyi
index 5521055bdef3a..83e114aac1a2a 100644
--- a/mypy/typeshed/stdlib/typing.pyi
+++ b/mypy/typeshed/stdlib/typing.pyi
@@ -640,14 +640,17 @@ class AsyncGenerator(AsyncIterator[_YieldT_co], Protocol[_YieldT_co, _SendT_cont
     ) -> Coroutine[Any, Any, _YieldT_co]: ...
     def aclose(self) -> Coroutine[Any, Any, None]: ...
 
+_ContainerT_contra = TypeVar("_ContainerT_contra", contravariant=True, default=Any)
+
 @runtime_checkable
-class Container(Protocol[_T_co]):
+class Container(Protocol[_ContainerT_contra]):
     # This is generic more on vibes than anything else
     @abstractmethod
-    def __contains__(self, x: object, /) -> bool: ...
+    def __contains__(self, x: _ContainerT_contra, /) -> bool: ...
 
 @runtime_checkable
-class Collection(Iterable[_T_co], Container[_T_co], Protocol[_T_co]):
+class Collection(Iterable[_T_co], Container[Any], Protocol[_T_co]):
+    # Note: need to use Container[Any] instead of Container[_T_co] to ensure covariance.
     # Implement Sized (but don't have it as a base class).
     @abstractmethod
     def __len__(self) -> int: ...
@@ -658,7 +661,7 @@ class Sequence(Reversible[_T_co], Collection[_T_co]):
     def __getitem__(self, index: int) -> _T_co: ...
     @overload
     @abstractmethod
-    def __getitem__(self, index: slice) -> Sequence[_T_co]: ...
+    def __getitem__(self, index: slice[int | None]) -> Sequence[_T_co]: ...
     # Mixin methods
     def index(self, value: Any, start: int = 0, stop: int = ...) -> int: ...
     def count(self, value: Any) -> int: ...
@@ -674,19 +677,19 @@ class MutableSequence(Sequence[_T]):
     def __getitem__(self, index: int) -> _T: ...
     @overload
     @abstractmethod
-    def __getitem__(self, index: slice) -> MutableSequence[_T]: ...
+    def __getitem__(self, index: slice[int | None]) -> MutableSequence[_T]: ...
     @overload
     @abstractmethod
     def __setitem__(self, index: int, value: _T) -> None: ...
     @overload
     @abstractmethod
-    def __setitem__(self, index: slice, value: Iterable[_T]) -> None: ...
+    def __setitem__(self, index: slice[int | None], value: Iterable[_T]) -> None: ...
     @overload
     @abstractmethod
     def __delitem__(self, index: int) -> None: ...
     @overload
     @abstractmethod
-    def __delitem__(self, index: slice) -> None: ...
+    def __delitem__(self, index: slice[int | None]) -> None: ...
     # Mixin methods
     def append(self, value: _T) -> None: ...
     def clear(self) -> None: ...
@@ -701,6 +704,8 @@ class AbstractSet(Collection[_T_co]):
     def __contains__(self, x: object) -> bool: ...
     def _hash(self) -> int: ...
     # Mixin methods
+    @classmethod
+    def _from_iterable(cls, it: Iterable[_S]) -> AbstractSet[_S]: ...
     def __le__(self, other: AbstractSet[Any]) -> bool: ...
     def __lt__(self, other: AbstractSet[Any]) -> bool: ...
     def __gt__(self, other: AbstractSet[Any]) -> bool: ...
@@ -733,6 +738,8 @@ class MappingView(Sized):
 
 class ItemsView(MappingView, AbstractSet[tuple[_KT_co, _VT_co]], Generic[_KT_co, _VT_co]):
     def __init__(self, mapping: SupportsGetItemViewable[_KT_co, _VT_co]) -> None: ...  # undocumented
+    @classmethod
+    def _from_iterable(cls, it: Iterable[_S]) -> set[_S]: ...
     def __and__(self, other: Iterable[Any]) -> set[tuple[_KT_co, _VT_co]]: ...
     def __rand__(self, other: Iterable[_T]) -> set[_T]: ...
     def __contains__(self, item: tuple[object, object]) -> bool: ...  # type: ignore[override]
@@ -746,6 +753,8 @@ class ItemsView(MappingView, AbstractSet[tuple[_KT_co, _VT_co]], Generic[_KT_co,
 
 class KeysView(MappingView, AbstractSet[_KT_co]):
     def __init__(self, mapping: Viewable[_KT_co]) -> None: ...  # undocumented
+    @classmethod
+    def _from_iterable(cls, it: Iterable[_S]) -> set[_S]: ...
     def __and__(self, other: Iterable[Any]) -> set[_KT_co]: ...
     def __rand__(self, other: Iterable[_T]) -> set[_T]: ...
     def __contains__(self, key: object) -> bool: ...
@@ -837,7 +846,7 @@ class MutableMapping(Mapping[_KT, _VT]):
     @overload
     def update(self: SupportsGetItem[str, _VT], m: Iterable[tuple[str, _VT]], /, **kwargs: _VT) -> None: ...
     @overload
-    def update(self: SupportsGetItem[str, _VT], **kwargs: _VT) -> None: ...
+    def update(self: SupportsGetItem[str, _VT], /, **kwargs: _VT) -> None: ...
 
 Text = str
 
diff --git a/mypy/typeshed/stdlib/typing_extensions.pyi b/mypy/typeshed/stdlib/typing_extensions.pyi
index 8a9f0f3919ba2..16cf0611a58ad 100644
--- a/mypy/typeshed/stdlib/typing_extensions.pyi
+++ b/mypy/typeshed/stdlib/typing_extensions.pyi
@@ -30,7 +30,7 @@ from collections.abc import (
 from contextlib import AbstractAsyncContextManager as AsyncContextManager, AbstractContextManager as ContextManager
 from re import Match as Match, Pattern as Pattern
 from types import GenericAlias, ModuleType
-from typing import (  # noqa: Y022,Y037,Y038,Y039,UP035
+from typing import (  # noqa: Y022,Y037,Y038,Y039,UP035,RUF100
     IO as IO,
     TYPE_CHECKING as TYPE_CHECKING,
     AbstractSet as AbstractSet,
diff --git a/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi b/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi
index 5c16bcc4ff233..d728fb975bfb9 100644
--- a/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi
+++ b/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi
@@ -123,14 +123,14 @@ class Element(Generic[_Tag]):
     @overload
     def __getitem__(self, key: SupportsIndex, /) -> Element: ...
     @overload
-    def __getitem__(self, key: slice, /) -> list[Element]: ...
+    def __getitem__(self, key: slice[SupportsIndex | None], /) -> list[Element]: ...
     def __len__(self) -> int: ...
     # Doesn't actually exist at runtime, but instance of the class are indeed iterable due to __getitem__.
     def __iter__(self) -> Iterator[Element]: ...
     @overload
     def __setitem__(self, key: SupportsIndex, value: Element[Any], /) -> None: ...
     @overload
-    def __setitem__(self, key: slice, value: Iterable[Element[Any]], /) -> None: ...
+    def __setitem__(self, key: slice[SupportsIndex | None], value: Iterable[Element[Any]], /) -> None: ...
 
     # Doesn't really exist in earlier versions, where __len__ is called implicitly instead
     @deprecated("Testing an element's truth value is deprecated.")