It sounds like that might be talking about the hyperlink `ping` param: https://developer.mozilla.org/en-US/docs/Web/API/HTMLAnchorE...

It could be marked as chrome because Firefox doesn’t support it (without a default-off config value) and Safari technically implemented it at a later date than Chrome, with non-chromium Edge supporting it years after chrome.

This would indicate Google is using chrome to tell it when (via its support of the ping property) but wouldn’t indicate they are decrypting and analyzing chrome sync data.