gh-90301: Doc: Add references to PEP 686 (#96816)

Doc: Add references to PEP 686.

1 files changed, 9 insertions, 7 deletions

diff --git a/Doc/library/io.rst b/Doc/library/io.rst
index 97a7064..7ec990c 100644
--- a/Doc/library/io.rst
+++ b/Doc/library/io.rst
@@ -123,17 +123,19 @@ encoding is not UTF-8 for most Windows users. For example::
    with open("README.md") as f:
        long_description = f.read()
 
-Additionally, while there is no concrete plan as of yet, Python may change
-the default text file encoding to UTF-8 in the future.
-
 Accordingly, it is highly recommended that you specify the encoding
 explicitly when opening text files. If you want to use UTF-8, pass
 ``encoding="utf-8"``. To use the current locale encoding,
-``encoding="locale"`` is supported in Python 3.10.
+``encoding="locale"`` is supported since Python 3.10.
+
+.. seealso::
+
+   :ref:`utf8-mode`
+      Python UTF-8 Mode can be used to change the default encoding to
+      UTF-8 from locale-specific encoding.
 
-When you need to run existing code on Windows that attempts to open
-UTF-8 files using the default locale encoding, you can enable the UTF-8
-mode. See :ref:`UTF-8 mode on Windows <win-utf8-mode>`.
+   :pep:`686`
+      Python 3.15 will make :ref:`utf8-mode` default.
 
 .. _io-encoding-warning: