These passkey QR codes don't need to use Web Bluetooth API, because they utilize the WebAuthn API. The website itself isn't given access to the bluetooth, the task is handed off to the browser, which as a native application, can access bluetooth and abstracts the bluetooth away.
replyThat's passkey QR codes generated by the browser, it has nothing to do with random QR codes offered by websites.
replyChrome does...
replyThat's news to me https://developer.mozilla.org/en-US/docs/Web/API/Web_Bluetoo...
replyWebsites cannot use Bluetooth anywhere. The QR codes shown in the blog post are not passkey QR codes, which is likely what's confusing you.
Interestingly, only on desktop/Android and not iOS it seems.
replyChrome on iOS uses WebKit, so that makes sense.
reply(*I think in the EU, iOS Chrome can use Blink, but I am not sure if it actually does.)