On Google Network Telemetry's Privacy Page you can request and collect all the privacy and GDPR related information that Google Network Telemetry is providing.
The privacy policy by is a legal document or statement that discloses how Google Network Telemetry gathers, uses, discloses, and manges their customers' data.
The basis for Google sharing, adding, uploading, hosting, accessing or sending personal data out of Europe. Vendors can also add a description of their own impact assessment for data transfers.