This was mentioned in the discussions and are an easy search away. Which means that googlers in their arrogance didn't do any research at all and that their counter underrepresents data as explicitly stated in their own document
https://www.loc.gov/standards/mods/mods-conversions.html
https://www.loc.gov/preservation/digital/formats/fdd/fdd_xml...
And then there's Congress: https://simonwillison.net/2025/Aug/19/xslt/