I read over the article's links now and what I said service wasn't quite right. This looks like it's based on the stub attribution technique but expands it beyond what those links describe. You can see the server side of the implementation at the links below

https://github.com/mozilla/bedrock/issues/9830

https://github.com/mozilla-services/stubattribution/pull/103

You'll see references to bouncer as well, which is https://github.com/mozilla-services/go-bouncer