diff --git a/stdlib/_csv.pyi b/stdlib/_csv.pyi
index c3f1dd58c..7e9b9e4e7 100644
--- a/stdlib/_csv.pyi
+++ b/stdlib/_csv.pyi
@@ -1,9 +1,9 @@
 from _typeshed import SupportsWrite
 from collections.abc import Iterable, Iterator
 from typing import Any
-from typing_extensions import Literal, TypeAlias
+from typing_extensions import Final, Literal, TypeAlias
 
-__version__: str
+__version__: Final[str]
 
 QUOTE_ALL: Literal[1]
 QUOTE_MINIMAL: Literal[0]
diff --git a/stdlib/_decimal.pyi b/stdlib/_decimal.pyi
index 3f997e7d9..b8208fe18 100644
--- a/stdlib/_decimal.pyi
+++ b/stdlib/_decimal.pyi
@@ -3,14 +3,14 @@ import sys
 from collections.abc import Container, Sequence
 from types import TracebackType
 from typing import Any, ClassVar, NamedTuple, overload
-from typing_extensions import Literal, Self, TypeAlias
+from typing_extensions import Final, Literal, Self, TypeAlias
 
 _Decimal: TypeAlias = Decimal | int
 _DecimalNew: TypeAlias = Decimal | float | str | tuple[int, Sequence[int], int]
 _ComparableNum: TypeAlias = Decimal | float | numbers.Rational
 
-__version__: str
-__libmpdec_version__: str
+__version__: Final[str]
+__libmpdec_version__: Final[str]
 
 class DecimalTuple(NamedTuple):
     sign: int
diff --git a/stdlib/_heapq.pyi b/stdlib/_heapq.pyi
index 90dc28deb..8d6c3e881 100644
--- a/stdlib/_heapq.pyi
+++ b/stdlib/_heapq.pyi
@@ -1,8 +1,9 @@
 from typing import Any, TypeVar
+from typing_extensions import Final
 
 _T = TypeVar("_T")
 
-__about__: str
+__about__: Final[str]
 
 def heapify(__heap: list[Any]) -> None: ...
 def heappop(__heap: list[_T]) -> _T: ...
diff --git a/stdlib/cgitb.pyi b/stdlib/cgitb.pyi
index 04bcbfb0d..4c315bf6c 100644
--- a/stdlib/cgitb.pyi
+++ b/stdlib/cgitb.pyi
@@ -2,8 +2,9 @@ from _typeshed import OptExcInfo, StrOrBytesPath
 from collections.abc import Callable
 from types import FrameType, TracebackType
 from typing import IO, Any
+from typing_extensions import Final
 
-__UNDEF__: object  # undocumented sentinel
+__UNDEF__: Final[object]  # undocumented sentinel
 
 def reset() -> str: ...  # undocumented
 def small(text: str) -> str: ...  # undocumented
diff --git a/stdlib/heapq.pyi b/stdlib/heapq.pyi
index 9d7815507..61418b370 100644
--- a/stdlib/heapq.pyi
+++ b/stdlib/heapq.pyi
@@ -2,12 +2,13 @@ from _heapq import *
 from _typeshed import SupportsRichComparison
 from collections.abc import Callable, Iterable
 from typing import Any, TypeVar
+from typing_extensions import Final
 
 __all__ = ["heappush", "heappop", "heapify", "heapreplace", "merge", "nlargest", "nsmallest", "heappushpop"]
 
 _S = TypeVar("_S")
 
-__about__: str
+__about__: Final[str]
 
 def merge(
     *iterables: Iterable[_S], key: Callable[[_S], SupportsRichComparison] | None = None, reverse: bool = False
diff --git a/stdlib/pydoc.pyi b/stdlib/pydoc.pyi
index 9bcd8659f..c6893d50c 100644
--- a/stdlib/pydoc.pyi
+++ b/stdlib/pydoc.pyi
@@ -6,16 +6,16 @@ from collections.abc import Callable, Container, Mapping, MutableMapping
 from reprlib import Repr
 from types import MethodType, ModuleType, TracebackType
 from typing import IO, Any, AnyStr, NoReturn, TypeVar
-from typing_extensions import TypeGuard
+from typing_extensions import Final, TypeGuard
 
 __all__ = ["help"]
 
 _T = TypeVar("_T")
 
-__author__: str
-__date__: str
-__version__: str
-__credits__: str
+__author__: Final[str]
+__date__: Final[str]
+__version__: Final[str]
+__credits__: Final[str]
 
 def pathdirs() -> list[str]: ...
 def getdoc(object: object) -> str: ...
diff --git a/stdlib/sys.pyi b/stdlib/sys.pyi
index 725f66794..e12881599 100644
--- a/stdlib/sys.pyi
+++ b/stdlib/sys.pyi
@@ -7,7 +7,7 @@ from importlib.machinery import ModuleSpec
 from io import TextIOWrapper
 from types import FrameType, ModuleType, TracebackType
 from typing import Any, NoReturn, Protocol, TextIO, TypeVar, overload
-from typing_extensions import Literal, TypeAlias, final
+from typing_extensions import Final, Literal, TypeAlias, final
 
 _T = TypeVar("_T")
 
@@ -62,9 +62,10 @@ stdout: TextIO
 stderr: TextIO
 if sys.version_info >= (3, 10):
     stdlib_module_names: frozenset[str]
-__stdin__: TextIOWrapper
-__stdout__: TextIOWrapper
-__stderr__: TextIOWrapper
+
+__stdin__: Final[TextIOWrapper]  # Contains the original value of stdin
+__stdout__: Final[TextIOWrapper]  # Contains the original value of stdout
+__stderr__: Final[TextIOWrapper]  # Contains the original value of stderr
 tracebacklimit: int
 version: str
 api_version: int
@@ -277,11 +278,10 @@ if sys.platform == "win32":
 
 def intern(__string: str) -> str: ...
 def is_finalizing() -> bool: ...
-
-__breakpointhook__: Any  # contains the original value of breakpointhook
-
 def breakpointhook(*args: Any, **kwargs: Any) -> Any: ...
 
+__breakpointhook__ = breakpointhook  # Contains the original value of breakpointhook
+
 if sys.platform != "win32":
     def setdlopenflags(__flags: int) -> None: ...
 
diff --git a/stdlib/unittest/mock.pyi b/stdlib/unittest/mock.pyi
index 3b1989edc..12ce2d2c7 100644
--- a/stdlib/unittest/mock.pyi
+++ b/stdlib/unittest/mock.pyi
@@ -3,7 +3,7 @@ from collections.abc import Awaitable, Callable, Coroutine, Iterable, Mapping, S
 from contextlib import _GeneratorContextManager
 from types import TracebackType
 from typing import Any, Generic, TypeVar, overload
-from typing_extensions import Literal, Self, TypeAlias
+from typing_extensions import Final, Literal, Self, TypeAlias
 
 _T = TypeVar("_T")
 _TT = TypeVar("_TT", bound=type[Any])
@@ -47,7 +47,7 @@ else:
         "seal",
     )
 
-__version__: str
+__version__: Final[str]
 
 FILTER_DIR: Any