Closes #21026: Augment site doc based on experiments. Patch by Carol Willing.
diff --git a/Doc/library/site.rst b/Doc/library/site.rst
index c450931..de3f751 100644
--- a/Doc/library/site.rst
+++ b/Doc/library/site.rst
@@ -83,7 +83,11 @@
 :mod:`sitecustomize`, which can perform arbitrary site-specific customizations.
 It is typically created by a system administrator in the site-packages
 directory.  If this import fails with an :exc:`ImportError` exception, it is
-silently ignored.
+silently ignored.  If Python is started without output streams available, as
+with :file:`pythonw.exe` on Windows (which is used by default to start IDLE),
+attempted output from :mod:`sitecustomize` is ignored. Any exception other
+than :exc:`ImportError` causes a silent and perhaps mysterious failure of the
+process.
 
 .. index:: module: usercustomize
 
diff --git a/Misc/ACKS b/Misc/ACKS
index 81d4aa9..2d08627 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1421,6 +1421,7 @@
 Jason Williams
 John Williams
 Sue Williams
+Carol Willing
 Steven Willis
 Frank Willison
 Geoff Wilson