@simon There's also a JSON API that doesn't require an accept header documented at https://warehouse.pypa.io/api-reference/json.html#get--pypi--project_name--json (e.g. https://pypi.org/pypi/pydantic/json) if you haven't seen that. (Not sure if this has the info you're looking for in the response.)
@jonafato that's not the same information, sadly - I'm looking for the new "provenance" key