Comment by vrtx0
Thank you! This is exactly the information the OP seems to have missed. It seems to confirm my suspicion that the author’s concerns about server-side privacy are unfounded — I think:
> The client decrypts the reply to its PNNS query, which may contain multiple candidate landmarks. A specialized, lightweight on-device reranking model then predicts the best candidate…
[please correct me if I missed anything — this used to be my field, but I’ve been disabled for 10 years now, so grain of salt]
The devil is in the proprietary details though.