wrong FNAME in tarfile if tgz extension is used

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-06-23.06:55:14.378>
labels = ['type-bug', 'library', '3.9', '3.10', '3.11']
title = 'wrong FNAME in tarfile if tgz extension is used'
updated_at = <Date 2022-01-16.17:58:03.979>
user = 'https://bugs.python.org/maciejmmmisiak'

bugs.python.org fields:

activity = <Date 2022-01-16.17:58:03.979>
actor = 'iritkatriel'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-06-23.06:55:14.378>
creator = 'maciej.mm.misiak'
dependencies = []
files = []
hgrepos = []
issue_num = 44495
keywords = []
message_count = 2.0
messages = ['396382', '405468']
nosy_count = 2.0
nosy_names = ['veaviticus', 'maciej.mm.misiak']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue44495'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']