With the release of 4.5.0, and specifically:

Merged databind.core and databind.json packages into databind. The old PyPI packages will remain as proxies until the next minor version.

novella fails to build documentation with a pkg_resource.DistributionNotFound exception complaining that databind.json isn't found, which is required by pydoc_markdown.novella.preprocessors.PydocTagPreprocessor.

I'm guessing this is due to the dummy/proxy package that databind.json provides after the merge.

Was able to get around the problem by pinning the version to 4.4.2.