On Google Cloud Access Transparency's Privacy Page you can request and collect all the privacy and GDPR related information that Google Cloud Access Transparency is providing.
The privacy policy by is a legal document or statement that discloses how Google Cloud Access Transparency 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.