Stefan did indeed receive, and was notified of, a 1-year ban from core development. This action was based on advice from the Conduct WG and our own deliberations. We wanted to have a discussion with him before we made this public. The SC sent him an email with details (quoted below), three weeks ago, CC'ing the Conduct WG. We had a brief back-and-forth last week. Unfortunately (and without telling us), Stefan apparently declined to address the matter in the way we asked.

For the record, the Steering Council followed the PEP 13 procedure for ejecting a core developer (https://www.python.org/dev/peps/pep-0013/#ejecting-core-team-members) and voted unanimously to eject Stefan, as we told Stefan we would do if he chose not to address the concerns we outlined below.

Our original message to Stefan:
"""
Dear Stefan,

The Python Steering Council and the PSF Conduct Working Group have received reports of your ongoing behavior in the Python core developer community. The Steering Council agrees with the Conduct Working Group’s findings that this behavior is unacceptable. While we appreciate your valuable technical contributions to CPython, that does not exempt you from the expected standards of behavior and the Code of Conduct.

Specifically, your behavior has displayed:

* Disrespectful, hostile, and unwelcoming communication in tone and content
* Harassment by needlessly adding people to issues
* A disregard of the directions and authority of the release manager

Some examples of the problematic behavior include:

* https://bugs.python.org/issue36839#msg344544
* https://bugs.python.org/issue40874#msg372616
* https://bugs.python.org/issue40874#msg372917
* https://bugs.python.org/issue40874#msg372922
* https://bugs.python.org/issue39542#msg372983

We are also aware that this is not new behavior. We know the PSF Conduct WG warned you on April 23, 2020 about your previous violations of the Code of Conduct.

As such, we are taking the action of suspending your participation in Python's development for 12 months starting today. You will lose access to:

* Python-committers
* Python-dev
* Python-ideas
* Core-mentorship
* bugs.python.org
* discuss.python.org
* The Python organization on GitHub

Along with the 12-month suspension, you will need to meet additional conditions in good faith:

* Please acknowledge that you have read and understand the Code of Conduct and promise to abide by it going forward
* You write an apology to your fellow core developers for your actions which we will publish on your behalf when announcing your suspension
* Acknowledge that future reinstatement will include a zero-tolerance conduct policy in regards to your future behavior

We offer you 14 days from today to meet these conditions and submit them to the Steering Council via email.

If you choose not to satisfy these conditions, the 12-month suspension will become a permanent ejection from the Python core developer community as per the procedures outlined in PEP 13.  You are then free to go through the Python core developer election process also as outlined in PEP 13, however the Steering Council will not consider approving any positive outcome of that vote until the 12-month suspension has elapsed.

- The Python Steering Council
"""

On behalf of the Steering Council,
Thomas.