`venv` → `ensurepip` may read local `setup.cfg` and fail mysteriously

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-09-07.18:15:21.876>
labels = ['type-bug', '3.9']
title = '`venv` \xe2\x86\x92 `ensurepip` may read local `setup.cfg` and fail mysteriously'
updated_at = <Date 2021-10-15.21:35:17.134>
user = 'https://github.com/nutjob4life'

bugs.python.org fields:

activity = <Date 2021-10-15.21:35:17.134>
actor = 'FFY00'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2021-09-07.18:15:21.876>
creator = 'nutjob4life'
dependencies = []
files = []
hgrepos = []
issue_num = 45131
keywords = []
message_count = 1.0
messages = ['401320']
nosy_count = 4.0
nosy_names = ['ncoghlan', 'dstufft', 'pradyunsg', 'nutjob4life']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue45131'
versions = ['Python 3.9']