gh-140693: Improve `argparse` documentation about controlling color (#140737)

diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 418f514995df3a9cf9748b54f1b5208ace29c860..9655db4f301a319d0916bbd4a290fac7533f9a5b 100644 (file)
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -638,6 +638,11 @@ by setting ``color`` to ``False``::
    ...                     help='an integer for the accumulator')
    >>> parser.parse_args(['--help'])
 
+Note that when ``color=True``, colored output depends on both environment
+variables and terminal capabilities.  However, if ``color=False``, colored
+output is always disabled, even if environment variables like ``FORCE_COLOR``
+are set.
+
 .. versionadded:: 3.14