Comment by tetha

Yep! I tested it with my own vibe-coded MITM proxy that hijacks pypi installations, which I created for ~$0.30 spend on DeepSeek API.

    $ python -m pip --no-cache install "pip @ https://files.pythonhosted.org/packages/3f/06/3e4420302363fbb71be3c7f35ce042f54bfca330e3e66b3a2e3c4cca579f/pip-26.2.2-py3-none-any.whl#sha256=fd7f4dfa8190e014013b9f08f3e973f4e4c26ffd179a204895533a7254813a70"
    Collecting pip @ https://files.pythonhosted.org/packages/3f/06/3e4420302363fbb71be3c7f35ce042f54bfca330e3e66b3a2e3c4cca579f/pip-26.2.2-py3-none-any.whl#sha256=fd7f4dfa8190e014013b9f08f3e973f4e4c26ffd179a204895533a7254813a70
      Downloading pip-26.2.2-py3-none-any.whl (1.8 MB)
         ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 1.8/1.8 MB 570.0 MB/s  0:00:00
    ERROR: THESE PACKAGES DO NOT MATCH THE HASHES FROM THE REQUIREMENTS FILE. If you have updated the package versions, please update the hashes. Otherwise, examine the package contents carefully; someone may have tampered with them.
        pip @ https://files.pythonhosted.org/packages/3f/06/3e4420302363fbb71be3c7f35ce042f54bfca330e3e66b3a2e3c4cca579f/pip-26.2.2-py3-none-any.whl#sha256=fd7f4dfa8190e014013b9f08f3e973f4e4c26ffd179a204895533a7254813a70 from https://files.pythonhosted.org/packages/3f/06/3e4420302363fbb71be3c7f35ce042f54bfca330e3e66b3a2e3c4cca579f/pip-26.2.2-py3-none-any.whl#sha256=fd7f4dfa8190e014013b9f08f3e973f4e4c26ffd179a204895533a7254813a70:
            Expected sha256 fd7f4dfa8190e014013b9f08f3e973f4e4c26ffd179a204895533a7254813a70
                 Got        8c448177668e735cdde7d6178694b90c084ba18559348cc394c4b1546eeec89c

The second one works too:

    $ PIP_USE_DEPRECATED=legacy-certs PIP_CERT=/etc/ssl/certs/ca-certificates.crt python -m pip install --no-cache --upgrade "pip>=26.2.2"
    WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1082)'))': /simple/pip/
    WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1082)'))': /simple/pip/
    WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1082)'))': /simple/pip/
    WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1082)'))': /simple/pip/
    WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1082)'))': /simple/pip/
    Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1082) - skipping
    ERROR: Could not find a version that satisfies the requirement pip>=26.2.2 (from versions: none)
    ERROR: No matching distribution found for pip>=26.2.2

As compared with a naive installation through the proxy:

    $ python -m pip --no-cache install 'pip>=26.2.2'
    Collecting pip>=26.2.2
      Downloading pip-26.2.2-py3-none-any.whl.metadata (4.6 kB)
    Downloading pip-26.2.2-py3-none-any.whl (1.8 MB)
       ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 1.8/1.8 MB 775.3 MB/s  0:00:00
    Installing collected packages: pip
      Attempting uninstall: pip
        Found existing installation: pip 26.2.1
        Uninstalling pip-26.2.1:
          Successfully uninstalled pip-26.2.1
    Successfully installed pip-26.2.2

    $ cat venv/lib/python3.14/site-packages/sni_proxy_sentinel.txt
    SNI proxy lab sentinel. This file is inert.