So is it normally allowed to publish a non-Google-affiliated repo under Google's brand? This seems weird to me, and I can't understand why he didn't just do it under his own name.
I did work at Google until a year ago, when I quit and sold my stock, but not in a team that remotely deals with open source so idk how this works.
This project is in an organization that has 57 other public repos with code by several other Google employees, is linked to by Google own documentation, and the only public member of the organization is (hopefully still) a Google employee.
Google has multiple Github Organizations that have all degrees of oficial-ness to it.
This is not someone releasing something in their private account and plastering Google logos over it.
Simply put: all work published to Google repos is implicitly affiliated with Google.
In my team's case we would include expectation-setting language in the README.md so that it was clear that the project was not an officially-supported Google product.
As far as I know, no-one ever lost their job for failing to set that expectation. A gentle correction from legal was sufficient to set the world right.