The o-o.myaddr.l.google.com domain is a feature of Google's authoritative name servers (ns[14].google.com) and not of 8.8.8.8. You can send similar queries through 1.1.1.1 (where you will see that there is no EDNS Client Subnet data provided, improving the privacy of your DNS but potentially returning less accurate answers, as Google's authoritative servers do not have your IP subnet, but only the IP address of the CloudFlare resolver forwarding your query.