Google has turned off access to sync features for Chromium
Here is the discussion on the Chromium embedder-dev mailing list: https://groups.google.com/a/chromium.org/g/embedder-dev/c/NX...Most interesting to me is that even though the Chrome team specifically provided API keys for open-source Chromium builds to use back in 2013, they are now claiming that "the Terms of Service don't allow this usage, and [the previous developer] didn't have authority to change the terms."