When looking at this issue...
I noticed that we have "wd": "https://www.wikidata.org/wiki/" in our Croissant output. We might want to change it to http (non-HTTPS) to be in line with this comment...
"For namespace URLs, we use http:// (that's an issue discussed at length in the schema.org community, and you can probably find an older issue about it.)" -- mlcommons/croissant#929 (review)
... or we could simply remove it since it doesn't seem to be used in our code and it appears in neither the Croissant 1.0 nor 1.1 spec.
I'm guessing that I copied that "wd" namespace from here: https://github.com/mlcommons/croissant/blob/v1.0.22/datasets/1.0/titanic/metadata.json#L46