The "WhatsApp Encryption Overview" technical whitepaper [1] had the following text removed between revisions:
"At no time does the WhatsApp server have access to any of the client's private keys."
[1] https://scontent.whatsapp.net/v/t39.8562-34/122249142_469857...
> The WhatsApp server has no access to the client’s private keys, (...)
>All chats use the same Signal protocol outlined in this whitepaper, regardless of their end-to-end encryption status. The WhatsApp server has no access to the client’s private keys, though if a business user delegates operation of their Business API client to a vendor, that vendor will have access to their private keys - including if that vendor is Facebook.
Not sure if the facebook exception was there in the previous version.
This is craftily ambiguous.
https://www.academia.edu/36044237/WhatsApp_Encryption_Overvi...
A copy I had downloaded on 29 July 2020