diff --git a/mypy/typeshed/stdlib/_interpreters.pyi b/mypy/typeshed/stdlib/_interpreters.pyi
index caa1115e9d3d..ad8eccbe3328 100644
--- a/mypy/typeshed/stdlib/_interpreters.pyi
+++ b/mypy/typeshed/stdlib/_interpreters.pyi
@@ -1,9 +1,10 @@
 import types
-from collections.abc import Callable, Mapping
-from typing import Final, Literal, SupportsIndex
+from collections.abc import Callable
+from typing import Any, Final, Literal, SupportsIndex
 from typing_extensions import TypeAlias
 
 _Configs: TypeAlias = Literal["default", "isolated", "legacy", "empty", ""]
+_SharedDict: TypeAlias = dict[str, Any]  # many objects can be shared
 
 class InterpreterError(Exception): ...
 class InterpreterNotFoundError(InterpreterError): ...
@@ -22,7 +23,11 @@ def is_running(id: SupportsIndex, *, restrict: bool = False) -> bool: ...
 def get_config(id: SupportsIndex, *, restrict: bool = False) -> types.SimpleNamespace: ...
 def whence(id: SupportsIndex) -> int: ...
 def exec(
-    id: SupportsIndex, code: str | types.CodeType | Callable[[], object], shared: bool | None = None, *, restrict: bool = False
+    id: SupportsIndex,
+    code: str | types.CodeType | Callable[[], object],
+    shared: _SharedDict | None = None,
+    *,
+    restrict: bool = False,
 ) -> None | types.SimpleNamespace: ...
 def call(
     id: SupportsIndex,
@@ -33,12 +38,16 @@ def call(
     restrict: bool = False,
 ) -> object: ...
 def run_string(
-    id: SupportsIndex, script: str | types.CodeType | Callable[[], object], shared: bool | None = None, *, restrict: bool = False
+    id: SupportsIndex,
+    script: str | types.CodeType | Callable[[], object],
+    shared: _SharedDict | None = None,
+    *,
+    restrict: bool = False,
 ) -> None: ...
 def run_func(
-    id: SupportsIndex, func: types.CodeType | Callable[[], object], shared: bool | None = None, *, restrict: bool = False
+    id: SupportsIndex, func: types.CodeType | Callable[[], object], shared: _SharedDict | None = None, *, restrict: bool = False
 ) -> None: ...
-def set___main___attrs(id: SupportsIndex, updates: Mapping[str, object], *, restrict: bool = False) -> None: ...
+def set___main___attrs(id: SupportsIndex, updates: _SharedDict, *, restrict: bool = False) -> None: ...
 def incref(id: SupportsIndex, *, implieslink: bool = False, restrict: bool = False) -> None: ...
 def decref(id: SupportsIndex, *, restrict: bool = False) -> None: ...
 def is_shareable(obj: object) -> bool: ...
diff --git a/mypy/typeshed/stdlib/_json.pyi b/mypy/typeshed/stdlib/_json.pyi
index 5296b8e62a02..cc59146ed982 100644
--- a/mypy/typeshed/stdlib/_json.pyi
+++ b/mypy/typeshed/stdlib/_json.pyi
@@ -11,7 +11,7 @@ class make_encoder:
     @property
     def key_separator(self) -> str: ...
     @property
-    def indent(self) -> int | None: ...
+    def indent(self) -> str | None: ...
     @property
     def markers(self) -> dict[int, Any] | None: ...
     @property
@@ -25,7 +25,7 @@ class make_encoder:
         markers: dict[int, Any] | None,
         default: Callable[[Any], Any],
         encoder: Callable[[str], str],
-        indent: int | None,
+        indent: str | None,
         key_separator: str,
         item_separator: str,
         sort_keys: bool,
diff --git a/mypy/typeshed/stdlib/_markupbase.pyi b/mypy/typeshed/stdlib/_markupbase.pyi
index 62bad25e5ccc..597bd09b700b 100644
--- a/mypy/typeshed/stdlib/_markupbase.pyi
+++ b/mypy/typeshed/stdlib/_markupbase.pyi
@@ -5,9 +5,9 @@ class ParserBase:
     def reset(self) -> None: ...
     def getpos(self) -> tuple[int, int]: ...
     def unknown_decl(self, data: str) -> None: ...
-    def parse_comment(self, i: int, report: int = 1) -> int: ...  # undocumented
+    def parse_comment(self, i: int, report: bool = True) -> int: ...  # undocumented
     def parse_declaration(self, i: int) -> int: ...  # undocumented
-    def parse_marked_section(self, i: int, report: int = 1) -> int: ...  # undocumented
+    def parse_marked_section(self, i: int, report: bool = True) -> int: ...  # undocumented
     def updatepos(self, i: int, j: int) -> int: ...  # undocumented
     if sys.version_info < (3, 10):
         # Removed from ParserBase: https://bugs.python.org/issue31844
diff --git a/mypy/typeshed/stdlib/ast.pyi b/mypy/typeshed/stdlib/ast.pyi
index 613940f5da6a..fcd6e8b01e74 100644
--- a/mypy/typeshed/stdlib/ast.pyi
+++ b/mypy/typeshed/stdlib/ast.pyi
@@ -1096,8 +1096,16 @@ class Constant(expr):
     kind: str | None
     if sys.version_info < (3, 14):
         # Aliases for value, for backwards compatibility
-        s: _ConstantValue
-        n: _ConstantValue
+        @deprecated("Will be removed in Python 3.14; use value instead")
+        @property
+        def n(self) -> _ConstantValue: ...
+        @n.setter
+        def n(self, value: _ConstantValue) -> None: ...
+        @deprecated("Will be removed in Python 3.14; use value instead")
+        @property
+        def s(self) -> _ConstantValue: ...
+        @s.setter
+        def s(self, value: _ConstantValue) -> None: ...
 
     def __init__(self, value: _ConstantValue, kind: str | None = None, **kwargs: Unpack[_Attributes]) -> None: ...
 
@@ -1495,11 +1503,11 @@ if sys.version_info >= (3, 10):
 
     class MatchSingleton(pattern):
         __match_args__ = ("value",)
-        value: Literal[True, False] | None
-        def __init__(self, value: Literal[True, False] | None, **kwargs: Unpack[_Attributes[int]]) -> None: ...
+        value: bool | None
+        def __init__(self, value: bool | None, **kwargs: Unpack[_Attributes[int]]) -> None: ...
 
         if sys.version_info >= (3, 14):
-            def __replace__(self, *, value: Literal[True, False] | None = ..., **kwargs: Unpack[_Attributes[int]]) -> Self: ...
+            def __replace__(self, *, value: bool | None = ..., **kwargs: Unpack[_Attributes[int]]) -> Self: ...
 
     class MatchSequence(pattern):
         __match_args__ = ("patterns",)
@@ -1696,25 +1704,23 @@ class _ABC(type):
 if sys.version_info < (3, 14):
     @deprecated("Replaced by ast.Constant; removed in Python 3.14")
     class Num(Constant, metaclass=_ABC):
-        value: int | float | complex
+        def __new__(cls, n: complex, **kwargs: Unpack[_Attributes]) -> Constant: ...  # type: ignore[misc]  # pyright: ignore[reportInconsistentConstructor]
 
     @deprecated("Replaced by ast.Constant; removed in Python 3.14")
     class Str(Constant, metaclass=_ABC):
-        value: str
-        # Aliases for value, for backwards compatibility
-        s: str
+        def __new__(cls, s: str, **kwargs: Unpack[_Attributes]) -> Constant: ...  # type: ignore[misc]  # pyright: ignore[reportInconsistentConstructor]
 
     @deprecated("Replaced by ast.Constant; removed in Python 3.14")
     class Bytes(Constant, metaclass=_ABC):
-        value: bytes
-        # Aliases for value, for backwards compatibility
-        s: bytes
+        def __new__(cls, s: bytes, **kwargs: Unpack[_Attributes]) -> Constant: ...  # type: ignore[misc]  # pyright: ignore[reportInconsistentConstructor]
 
     @deprecated("Replaced by ast.Constant; removed in Python 3.14")
-    class NameConstant(Constant, metaclass=_ABC): ...
+    class NameConstant(Constant, metaclass=_ABC):
+        def __new__(cls, value: _ConstantValue, kind: str | None, **kwargs: Unpack[_Attributes]) -> Constant: ...  # type: ignore[misc]  # pyright: ignore[reportInconsistentConstructor]
 
     @deprecated("Replaced by ast.Constant; removed in Python 3.14")
-    class Ellipsis(Constant, metaclass=_ABC): ...
+    class Ellipsis(Constant, metaclass=_ABC):
+        def __new__(cls, **kwargs: Unpack[_Attributes]) -> Constant: ...  # type: ignore[misc]  # pyright: ignore[reportInconsistentConstructor]
 
 # everything below here is defined in ast.py
 
@@ -1797,7 +1803,7 @@ if sys.version_info >= (3, 13):
         type_comments: bool = False,
         feature_version: None | int | tuple[int, int] = None,
         optimize: Literal[-1, 0, 1, 2] = -1,
-    ) -> AST: ...
+    ) -> mod: ...
 
 else:
     @overload
@@ -1868,7 +1874,7 @@ else:
         *,
         type_comments: bool = False,
         feature_version: None | int | tuple[int, int] = None,
-    ) -> AST: ...
+    ) -> mod: ...
 
 def literal_eval(node_or_string: str | AST) -> Any: ...
 
diff --git a/mypy/typeshed/stdlib/asyncio/__init__.pyi b/mypy/typeshed/stdlib/asyncio/__init__.pyi
index 68e44a88face..58739816a67e 100644
--- a/mypy/typeshed/stdlib/asyncio/__init__.pyi
+++ b/mypy/typeshed/stdlib/asyncio/__init__.pyi
@@ -1,4 +1,4 @@
-# ruff: noqa: PLR5501 # This condition is so big, it's clearer to keep to platform condition in two blocks
+# This condition is so big, it's clearer to keep to platform condition in two blocks
 # Can't NOQA on a specific line: https://github.com/plinss/flake8-noqa/issues/22
 import sys
 from collections.abc import Awaitable, Coroutine, Generator
diff --git a/mypy/typeshed/stdlib/builtins.pyi b/mypy/typeshed/stdlib/builtins.pyi
index 6e983ef9ef29..b853330b18fb 100644
--- a/mypy/typeshed/stdlib/builtins.pyi
+++ b/mypy/typeshed/stdlib/builtins.pyi
@@ -609,7 +609,7 @@ class bytes(Sequence[int]):
     def strip(self, bytes: ReadableBuffer | None = None, /) -> bytes: ...
     def swapcase(self) -> bytes: ...
     def title(self) -> bytes: ...
-    def translate(self, table: ReadableBuffer | None, /, delete: bytes = b"") -> bytes: ...
+    def translate(self, table: ReadableBuffer | None, /, delete: ReadableBuffer = b"") -> bytes: ...
     def upper(self) -> bytes: ...
     def zfill(self, width: SupportsIndex, /) -> bytes: ...
     @classmethod
diff --git a/mypy/typeshed/stdlib/collections/__init__.pyi b/mypy/typeshed/stdlib/collections/__init__.pyi
index b9e4f84ec0b6..bc33d91caa1d 100644
--- a/mypy/typeshed/stdlib/collections/__init__.pyi
+++ b/mypy/typeshed/stdlib/collections/__init__.pyi
@@ -108,6 +108,8 @@ class UserDict(MutableMapping[_KT, _VT]):
         @overload
         def get(self, key: _KT, default: None = None) -> _VT | None: ...
         @overload
+        def get(self, key: _KT, default: _VT) -> _VT: ...
+        @overload
         def get(self, key: _KT, default: _T) -> _VT | _T: ...
 
 class UserList(MutableSequence[_T]):
@@ -452,6 +454,8 @@ class ChainMap(MutableMapping[_KT, _VT]):
     @overload
     def get(self, key: _KT, default: None = None) -> _VT | None: ...
     @overload
+    def get(self, key: _KT, default: _VT) -> _VT: ...
+    @overload
     def get(self, key: _KT, default: _T) -> _VT | _T: ...
     def __missing__(self, key: _KT) -> _VT: ...  # undocumented
     def __bool__(self) -> bool: ...
diff --git a/mypy/typeshed/stdlib/compression/bz2/__init__.pyi b/mypy/typeshed/stdlib/compression/bz2.pyi
similarity index 100%
rename from mypy/typeshed/stdlib/compression/bz2/__init__.pyi
rename to mypy/typeshed/stdlib/compression/bz2.pyi
diff --git a/mypy/typeshed/stdlib/compression/gzip/__init__.pyi b/mypy/typeshed/stdlib/compression/gzip.pyi
similarity index 100%
rename from mypy/typeshed/stdlib/compression/gzip/__init__.pyi
rename to mypy/typeshed/stdlib/compression/gzip.pyi
diff --git a/mypy/typeshed/stdlib/compression/lzma/__init__.pyi b/mypy/typeshed/stdlib/compression/lzma.pyi
similarity index 100%
rename from mypy/typeshed/stdlib/compression/lzma/__init__.pyi
rename to mypy/typeshed/stdlib/compression/lzma.pyi
diff --git a/mypy/typeshed/stdlib/compression/zlib/__init__.pyi b/mypy/typeshed/stdlib/compression/zlib.pyi
similarity index 100%
rename from mypy/typeshed/stdlib/compression/zlib/__init__.pyi
rename to mypy/typeshed/stdlib/compression/zlib.pyi
diff --git a/mypy/typeshed/stdlib/compression/zstd/_zstdfile.pyi b/mypy/typeshed/stdlib/compression/zstd/_zstdfile.pyi
index 045b2d35acfe..e67b3d992f2f 100644
--- a/mypy/typeshed/stdlib/compression/zstd/_zstdfile.pyi
+++ b/mypy/typeshed/stdlib/compression/zstd/_zstdfile.pyi
@@ -3,7 +3,7 @@ from collections.abc import Mapping
 from compression._common import _streams
 from compression.zstd import ZstdDict
 from io import TextIOWrapper, _WrappedBuffer
-from typing import Literal, overload, type_check_only
+from typing import Literal, Protocol, overload, type_check_only
 from typing_extensions import TypeAlias
 
 from _zstd import ZstdCompressor, _ZstdCompressorFlushBlock, _ZstdCompressorFlushFrame
@@ -16,11 +16,11 @@ _ReadTextMode: TypeAlias = Literal["rt"]
 _WriteTextMode: TypeAlias = Literal["wt", "xt", "at"]
 
 @type_check_only
-class _FileBinaryRead(_streams._Reader):
+class _FileBinaryRead(_streams._Reader, Protocol):
     def close(self) -> None: ...
 
 @type_check_only
-class _FileBinaryWrite(SupportsWrite[bytes]):
+class _FileBinaryWrite(SupportsWrite[bytes], Protocol):
     def close(self) -> None: ...
 
 class ZstdFile(_streams.BaseStream):
diff --git a/mypy/typeshed/stdlib/ctypes/__init__.pyi b/mypy/typeshed/stdlib/ctypes/__init__.pyi
index 0b14bd856784..52288d011e98 100644
--- a/mypy/typeshed/stdlib/ctypes/__init__.pyi
+++ b/mypy/typeshed/stdlib/ctypes/__init__.pyi
@@ -32,7 +32,7 @@ if sys.platform == "win32":
     from _ctypes import FormatError as FormatError, get_last_error as get_last_error, set_last_error as set_last_error
 
     if sys.version_info >= (3, 14):
-        from _ctypes import COMError as COMError
+        from _ctypes import COMError as COMError, CopyComPointer as CopyComPointer
 
 if sys.version_info >= (3, 11):
     from ctypes._endian import BigEndianUnion as BigEndianUnion, LittleEndianUnion as LittleEndianUnion
diff --git a/mypy/typeshed/stdlib/html/parser.pyi b/mypy/typeshed/stdlib/html/parser.pyi
index d322ade965d9..5d38c9c0d800 100644
--- a/mypy/typeshed/stdlib/html/parser.pyi
+++ b/mypy/typeshed/stdlib/html/parser.pyi
@@ -21,7 +21,7 @@ class HTMLParser(ParserBase):
     def check_for_whole_start_tag(self, i: int) -> int: ...  # undocumented
     def clear_cdata_mode(self) -> None: ...  # undocumented
     def goahead(self, end: bool) -> None: ...  # undocumented
-    def parse_bogus_comment(self, i: int, report: bool = ...) -> int: ...  # undocumented
+    def parse_bogus_comment(self, i: int, report: bool = True) -> int: ...  # undocumented
     def parse_endtag(self, i: int) -> int: ...  # undocumented
     def parse_html_declaration(self, i: int) -> int: ...  # undocumented
     def parse_pi(self, i: int) -> int: ...  # undocumented
diff --git a/mypy/typeshed/stdlib/importlib/metadata/__init__.pyi b/mypy/typeshed/stdlib/importlib/metadata/__init__.pyi
index 15d8b50b09d2..789878382ceb 100644
--- a/mypy/typeshed/stdlib/importlib/metadata/__init__.pyi
+++ b/mypy/typeshed/stdlib/importlib/metadata/__init__.pyi
@@ -140,6 +140,8 @@ if sys.version_info >= (3, 10) and sys.version_info < (3, 12):
         @overload
         def get(self, name: _KT, default: None = None) -> _VT | None: ...
         @overload
+        def get(self, name: _KT, default: _VT) -> _VT: ...
+        @overload
         def get(self, name: _KT, default: _T) -> _VT | _T: ...
         def __iter__(self) -> Iterator[_KT]: ...
         def __contains__(self, *args: object) -> bool: ...
diff --git a/mypy/typeshed/stdlib/string/templatelib.pyi b/mypy/typeshed/stdlib/string/templatelib.pyi
index 324447f5f34c..3f460006a796 100644
--- a/mypy/typeshed/stdlib/string/templatelib.pyi
+++ b/mypy/typeshed/stdlib/string/templatelib.pyi
@@ -26,6 +26,6 @@ class Interpolation:
     __match_args__ = ("value", "expression", "conversion", "format_spec")
 
     def __new__(
-        cls, value: Any, expression: str, conversion: Literal["a", "r", "s"] | None = None, format_spec: str = ""
+        cls, value: Any, expression: str = "", conversion: Literal["a", "r", "s"] | None = None, format_spec: str = ""
     ) -> Interpolation: ...
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
diff --git a/mypy/typeshed/stdlib/sys/__init__.pyi b/mypy/typeshed/stdlib/sys/__init__.pyi
index 054fe91b17c6..0ca30396a878 100644
--- a/mypy/typeshed/stdlib/sys/__init__.pyi
+++ b/mypy/typeshed/stdlib/sys/__init__.pyi
@@ -345,6 +345,10 @@ else:
 
 def _current_frames() -> dict[int, FrameType]: ...
 def _getframe(depth: int = 0, /) -> FrameType: ...
+
+if sys.version_info >= (3, 12):
+    def _getframemodulename(depth: int = 0) -> str | None: ...
+
 def _debugmallocstats() -> None: ...
 def __displayhook__(object: object, /) -> None: ...
 def __excepthook__(exctype: type[BaseException], value: BaseException, traceback: TracebackType | None, /) -> None: ...
diff --git a/mypy/typeshed/stdlib/tarfile.pyi b/mypy/typeshed/stdlib/tarfile.pyi
index a18ef0b823f9..dba250f2d353 100644
--- a/mypy/typeshed/stdlib/tarfile.pyi
+++ b/mypy/typeshed/stdlib/tarfile.pyi
@@ -9,6 +9,9 @@ from types import TracebackType
 from typing import IO, ClassVar, Literal, Protocol, overload
 from typing_extensions import Self, TypeAlias, deprecated
 
+if sys.version_info >= (3, 14):
+    from compression.zstd import ZstdDict
+
 __all__ = [
     "TarFile",
     "TarInfo",
@@ -186,6 +189,30 @@ class TarFile:
         debug: int | None = ...,
         errorlevel: int | None = ...,
     ) -> Self: ...
+    if sys.version_info >= (3, 14):
+        @overload
+        @classmethod
+        def open(
+            cls,
+            name: StrOrBytesPath | None,
+            mode: Literal["r:zst"],
+            fileobj: _Fileobj | None = None,
+            bufsize: int = 10240,
+            *,
+            format: int | None = ...,
+            tarinfo: type[TarInfo] | None = ...,
+            dereference: bool | None = ...,
+            ignore_zeros: bool | None = ...,
+            encoding: str | None = ...,
+            errors: str = ...,
+            pax_headers: Mapping[str, str] | None = ...,
+            debug: int | None = ...,
+            errorlevel: int | None = ...,
+            level: None = None,
+            options: Mapping[int, int] | None = None,
+            zstd_dict: ZstdDict | None = None,
+        ) -> Self: ...
+
     @overload
     @classmethod
     def open(
@@ -304,12 +331,56 @@ class TarFile:
         errorlevel: int | None = ...,
         preset: Literal[0, 1, 2, 3, 4, 5, 6, 7, 8, 9] | None = ...,
     ) -> Self: ...
+    if sys.version_info >= (3, 14):
+        @overload
+        @classmethod
+        def open(
+            cls,
+            name: StrOrBytesPath | None,
+            mode: Literal["x:zst", "w:zst"],
+            fileobj: _Fileobj | None = None,
+            bufsize: int = 10240,
+            *,
+            format: int | None = ...,
+            tarinfo: type[TarInfo] | None = ...,
+            dereference: bool | None = ...,
+            ignore_zeros: bool | None = ...,
+            encoding: str | None = ...,
+            errors: str = ...,
+            pax_headers: Mapping[str, str] | None = ...,
+            debug: int | None = ...,
+            errorlevel: int | None = ...,
+            options: Mapping[int, int] | None = None,
+            zstd_dict: ZstdDict | None = None,
+        ) -> Self: ...
+        @overload
+        @classmethod
+        def open(
+            cls,
+            name: StrOrBytesPath | None = None,
+            *,
+            mode: Literal["x:zst", "w:zst"],
+            fileobj: _Fileobj | None = None,
+            bufsize: int = 10240,
+            format: int | None = ...,
+            tarinfo: type[TarInfo] | None = ...,
+            dereference: bool | None = ...,
+            ignore_zeros: bool | None = ...,
+            encoding: str | None = ...,
+            errors: str = ...,
+            pax_headers: Mapping[str, str] | None = ...,
+            debug: int | None = ...,
+            errorlevel: int | None = ...,
+            options: Mapping[int, int] | None = None,
+            zstd_dict: ZstdDict | None = None,
+        ) -> Self: ...
+
     @overload
     @classmethod
     def open(
         cls,
         name: StrOrBytesPath | ReadableBuffer | None,
-        mode: Literal["r|*", "r|", "r|gz", "r|bz2", "r|xz"],
+        mode: Literal["r|*", "r|", "r|gz", "r|bz2", "r|xz", "r|zst"],
         fileobj: _Fileobj | None = None,
         bufsize: int = 10240,
         *,
@@ -329,7 +400,7 @@ class TarFile:
         cls,
         name: StrOrBytesPath | ReadableBuffer | None = None,
         *,
-        mode: Literal["r|*", "r|", "r|gz", "r|bz2", "r|xz"],
+        mode: Literal["r|*", "r|", "r|gz", "r|bz2", "r|xz", "r|zst"],
         fileobj: _Fileobj | None = None,
         bufsize: int = 10240,
         format: int | None = ...,
@@ -347,7 +418,7 @@ class TarFile:
     def open(
         cls,
         name: StrOrBytesPath | WriteableBuffer | None,
-        mode: Literal["w|", "w|xz"],
+        mode: Literal["w|", "w|xz", "w|zst"],
         fileobj: _Fileobj | None = None,
         bufsize: int = 10240,
         *,
@@ -367,7 +438,7 @@ class TarFile:
         cls,
         name: StrOrBytesPath | WriteableBuffer | None = None,
         *,
-        mode: Literal["w|", "w|xz"],
+        mode: Literal["w|", "w|xz", "w|zst"],
         fileobj: _Fileobj | None = None,
         bufsize: int = 10240,
         format: int | None = ...,
@@ -526,6 +597,48 @@ class TarFile:
         debug: int | None = ...,
         errorlevel: int | None = ...,
     ) -> Self: ...
+    if sys.version_info >= (3, 14):
+        @overload
+        @classmethod
+        def zstopen(
+            cls,
+            name: StrOrBytesPath | None,
+            mode: Literal["r"] = "r",
+            fileobj: IO[bytes] | None = None,
+            level: None = None,
+            options: Mapping[int, int] | None = None,
+            zstd_dict: ZstdDict | None = None,
+            *,
+            format: int | None = ...,
+            tarinfo: type[TarInfo] | None = ...,
+            dereference: bool | None = ...,
+            ignore_zeros: bool | None = ...,
+            encoding: str | None = ...,
+            pax_headers: Mapping[str, str] | None = ...,
+            debug: int | None = ...,
+            errorlevel: int | None = ...,
+        ) -> Self: ...
+        @overload
+        @classmethod
+        def zstopen(
+            cls,
+            name: StrOrBytesPath | None,
+            mode: Literal["w", "x"],
+            fileobj: IO[bytes] | None = None,
+            level: int | None = None,
+            options: Mapping[int, int] | None = None,
+            zstd_dict: ZstdDict | None = None,
+            *,
+            format: int | None = ...,
+            tarinfo: type[TarInfo] | None = ...,
+            dereference: bool | None = ...,
+            ignore_zeros: bool | None = ...,
+            encoding: str | None = ...,
+            pax_headers: Mapping[str, str] | None = ...,
+            debug: int | None = ...,
+            errorlevel: int | None = ...,
+        ) -> Self: ...
+
     def getmember(self, name: str) -> TarInfo: ...
     def getmembers(self) -> _list[TarInfo]: ...
     def getnames(self) -> _list[str]: ...
diff --git a/mypy/typeshed/stdlib/types.pyi b/mypy/typeshed/stdlib/types.pyi
index 582cb653422f..44bd3eeb3f53 100644
--- a/mypy/typeshed/stdlib/types.pyi
+++ b/mypy/typeshed/stdlib/types.pyi
@@ -323,7 +323,9 @@ class MappingProxyType(Mapping[_KT, _VT_co]):
     @overload
     def get(self, key: _KT, /) -> _VT_co | None: ...
     @overload
-    def get(self, key: _KT, default: _VT_co | _T2, /) -> _VT_co | _T2: ...
+    def get(self, key: _KT, default: _VT_co, /) -> _VT_co: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues] # Covariant type as parameter
+    @overload
+    def get(self, key: _KT, default: _T2, /) -> _VT_co | _T2: ...
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
     def __reversed__(self) -> Iterator[_KT]: ...
     def __or__(self, value: Mapping[_T1, _T2], /) -> dict[_KT | _T1, _VT_co | _T2]: ...
diff --git a/mypy/typeshed/stdlib/typing.pyi b/mypy/typeshed/stdlib/typing.pyi
index 79ab9eee924f..d296c8d92149 100644
--- a/mypy/typeshed/stdlib/typing.pyi
+++ b/mypy/typeshed/stdlib/typing.pyi
@@ -1,5 +1,4 @@
 # Since this module defines "overload" it is not recognized by Ruff as typing.overload
-# ruff: noqa: F811
 # TODO: The collections import is required, otherwise mypy crashes.
 # https://github.com/python/mypy/issues/16744
 import collections  # noqa: F401  # pyright: ignore[reportUnusedImport]
@@ -746,7 +745,9 @@ class Mapping(Collection[_KT], Generic[_KT, _VT_co]):
     @overload
     def get(self, key: _KT, /) -> _VT_co | None: ...
     @overload
-    def get(self, key: _KT, /, default: _VT_co | _T) -> _VT_co | _T: ...
+    def get(self, key: _KT, /, default: _VT_co) -> _VT_co: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues] # Covariant type as parameter
+    @overload
+    def get(self, key: _KT, /, default: _T) -> _VT_co | _T: ...
     def items(self) -> ItemsView[_KT, _VT_co]: ...
     def keys(self) -> KeysView[_KT]: ...
     def values(self) -> ValuesView[_VT_co]: ...
diff --git a/mypy/typeshed/stdlib/urllib/error.pyi b/mypy/typeshed/stdlib/urllib/error.pyi
index 89cec9bf289c..2173d7e6efaa 100644
--- a/mypy/typeshed/stdlib/urllib/error.pyi
+++ b/mypy/typeshed/stdlib/urllib/error.pyi
@@ -6,6 +6,8 @@ __all__ = ["URLError", "HTTPError", "ContentTooShortError"]
 
 class URLError(OSError):
     reason: str | BaseException
+    # The `filename` attribute only exists if it was provided to `__init__` and wasn't `None`.
+    filename: str
     def __init__(self, reason: str | BaseException, filename: str | None = None) -> None: ...
 
 class HTTPError(URLError, addinfourl):
@@ -16,6 +18,9 @@ class HTTPError(URLError, addinfourl):
     @property
     def reason(self) -> str: ...  # type: ignore[override]
     code: int
+    msg: str
+    hdrs: Message
+    fp: IO[bytes]
     def __init__(self, url: str, code: int, msg: str, hdrs: Message, fp: IO[bytes] | None) -> None: ...
 
 class ContentTooShortError(URLError):
diff --git a/mypy/typeshed/stdlib/weakref.pyi b/mypy/typeshed/stdlib/weakref.pyi
index 593eb4615c8f..334fab7e7468 100644
--- a/mypy/typeshed/stdlib/weakref.pyi
+++ b/mypy/typeshed/stdlib/weakref.pyi
@@ -99,6 +99,8 @@ class WeakValueDictionary(MutableMapping[_KT, _VT]):
     @overload
     def get(self, key: _KT, default: None = None) -> _VT | None: ...
     @overload
+    def get(self, key: _KT, default: _VT) -> _VT: ...
+    @overload
     def get(self, key: _KT, default: _T) -> _VT | _T: ...
     # These are incompatible with Mapping
     def keys(self) -> Iterator[_KT]: ...  # type: ignore[override]
@@ -149,6 +151,8 @@ class WeakKeyDictionary(MutableMapping[_KT, _VT]):
     @overload
     def get(self, key: _KT, default: None = None) -> _VT | None: ...
     @overload
+    def get(self, key: _KT, default: _VT) -> _VT: ...
+    @overload
     def get(self, key: _KT, default: _T) -> _VT | _T: ...
     # These are incompatible with Mapping
     def keys(self) -> Iterator[_KT]: ...  # type: ignore[override]