The links to APIs I see on that page are https://developers.google.com/resources/api-libraries/docume... and https://developers.google.com/api-client-library/python/ , both work for me. The latter in turn points to https://cloud.google.com/tasks/ (Tasks Alpha) which also works for me. Maybe it only works for customers enrolled in the limited-access Alpha and as a Googler I'm automatically enrolled without knowing that...? But, I can also see the latter in an incognito window in Chrome...