[3.13] gh-76637: Note that undefined Codec is for testing (GH-136531) (#136537)

miss-islington · StanFromIreland · web-flow · commit 175ada2806ab · 2025-07-11T10:57:39.000Z
gh-76637: Note that `undefined` Codec is for testing (GH-136531) Closes GH-76637 (cherry picked from commit 975b57d) Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>
diff --git a/Doc/library/codecs.rst b/Doc/library/codecs.rst
@@ -1384,7 +1384,11 @@ encodings.
 |                    |         | It is used in the Python  |
 |                    |         | pickle protocol.          |
 +--------------------+---------+---------------------------+
-| undefined          |         | Raise an exception for    |
+| undefined          |         | This Codec should only    |
+|                    |         | be used for testing       |
+|                    |         | purposes.                 |
+|                    |         |                           |
+|                    |         | Raise an exception for    |
 |                    |         | all conversions, even     |
 |                    |         | empty strings. The error  |
 |                    |         | handler is ignored.       |
