Lawrence Kesteloot noted: Lib/user.py has a comment that says that the
script pointed to by PYTHONPATH will be executed on startup. That
should say PYTHONSTARTUP.
diff --git a/Lib/user.py b/Lib/user.py
index 1374c11..ee8ed88 100644
--- a/Lib/user.py
+++ b/Lib/user.py
@@ -2,7 +2,7 @@
As a policy, Python doesn't run user-specified code on startup of
Python programs (interactive sessions execute the script specified in
-the PYTHONPATH environment variable if it exists).
+the PYTHONSTARTUP environment variable if it exists).
However, some programs or sites may find it convenient to allow users
to have a standard customization file, which gets run when a program