Python backoff repository was archived
github.com
github.com
The project is abandoned, with the last update from Jan 20, 2023.
I see 154 outstanding forks, and the potential to create more. Perhaps an existing one has non-trivial amounts of stars/watchers?
That said, a fork can't just publish a new version on PyPI under the original name. That requires at minimum a PEP 541 request (https://peps.python.org/pep-0541/#continued-maintenance-of-a...).
You could also try contacting the author at the email provided in pyproject.toml (or the one on said author's GitHub profile), I suppose.