Releases are done to PyPI directly from the main branch.
This usually happens after every merge. Check the commit log and the date of the latest PyPI release to see which changes are included.
To publish a release, first make sure that the version number in setup.cfg is increased.
Otherwise, publishing will give an error.
Then manually trigger the "Publish canonical-sphinx-extensions to PyPI" workflow on the main branch. To do so, you must have Write permission on the repository.