Yes, that article states that as well under limitations: "Deprecation status: While functional, Apple discourages its direct use in favor of App Sandbox for developers."
Good information, but you can already turn this off via the (quite hidden, I admit) setting that is mentioned in the article. That's a better way to turn this off completely, rather than patch it via a visual rule.
Brave browser does not have an option to turn it off but uBlock Origin custom filter works.
In the Brave community the only solution offered was an adblock filter:
brave://adblock (custom filter) ||accounts.google.com/gsi/client$script,third-party
Either way it's something you'd need to go out of your way to configure any time you interact with a new web browser. And both ways can be disabled randomly (Chrome settings changes during browser updates, or uBlock extension being deprecated).
That does not completely turn off the federated sign-in popup you see on the top right in various websites. The solution is actually already mentioned in the article.
