So I went and had a look. There's no specification there that I could see - is there a more specific link I missed?
The white paper was issued in 2018. Is that what there is?
The product is Entra Verified ID - which turns out to be a directory service on Azure. https://docs.microsoft.com/en-us/azure/active-directory/veri...
This appears for all the world like a centralised product marketing itself as "decentralised".