The author has a @google.com email address.
Also, I don't know if it's commonplace anymore, but I remember in the past a lot of people that worked on Chrome had @chromium.org addresses, too.
Some relevant links are https://opensource.google.com/docs/releasing/ for the personal-project-with-Google-copyright flow and https://opensource.google.com/docs/iarc/ for the personal-copyright flow.