__PYVENV_LAUNCHER__ is not picked up by the
site during startup. See #3175 (closed)
Alternatively, it could just be removed without being restored as well, I believe (this is what CPython is planning, anyway: https://github.com/python/cpython/pull/9516)
I've search for
import site, but I'm not sure if I got all places in PyPy where
site is imported during startup?
I'm also not entirely sure how to best test it?