> Also consider that Apple zeroes out attestation for its devices

This may be the saving grace because it may end up being that whether or not attestation is part of the standard doesn't matter because companies won't be able to use it. But it doesn't mean that attestation is harmless, it means that we're very lucky that (for now) Apple is deciding to effectively make it impossible for a commercial service to actually use it reliably.

> It prevents you from using security keys that aren't configured for user verification, and they don't do that through attestation.

Fair point, I don't know that this is actually using attestation and that it's not just the Yubikey reporting back that it doesn't support that field. I do quibble somewhat with "they're not blocking Yubikeys, they're just blocking <description of a Yubikey>." But... yeah, I'll grant you're probably right that this is not using attestation.

> I don't see a world where you can export passkeys from Apple iCloud Keychain and import them into Google Password Manager.

That's exactly what I mean when I say it wouldn't be sufficient. When I talk about syncing, I'm talking about transferring into and out of ecosystems, not just specific devices. What you're describing is a system where I can use the KeePassXC ecosystem to use keys across multiple devices. But I can't transfer those keys out of the KeePassXC ecosystem (unless hopefully other vendors like 1Password add support), and if someone starts using iCloud, they're stuck with same vendor lock-in.

This is effectively saying, "you'll have a closed ecosystem for most people, but people who know enough beforehand to avoid it can somewhat avoid it." We should expect better from a standards body that purports to be building an Open standard.

I really don't see how this is an out-of-scope problem for the FIDO Alliance. They have input from every single major OS. All of the players are in the same space. And their entire job is to dictate how this is going to work. I'm just asking them to do that job. A spec for portability is not that big of an ask compared to everything else they're already working on as part of this.

It's not really that different than a spec for logging in using a standardized QR code, or over Bluetooth -- all of which was considered in-scope for them to to work on. Portability is just part of the general interoperability work that we should be expecting them to do.

> Do you want your browser deciding for you what websites you can log in to?

Of course not; in very typical fashion Google's solution to the problem may be worse than the problem itself. Google is very fond of recognizing that a feature is abusable and saying, "well, how about we prevent that abuse by giving ourselves even more capricious power?"

But I do think it shows I'm not being paranoid, that this is a legitimate worry that even Google recognizes is worth worrying about. Google is part of the FIDO Alliance and it's not looking at attestation as a theoretical risk; it's looking at it as a very plausible risk that it needs to have policies around.

Which I think is pretty reasonable given that every single instance of attestation in the past has been used for DRM, and there's nothing special about attestation in this spec that would stop that from happening. I really do think the burden of proof here is on you to describe why you think Netflix/Banks/etc... are suddenly going to act differently now than they have with every other attestation method they've had access to leading up to now.

The only answer I can think of is, "they'll act differently because Apple is effectively killing attestation for platform keys for everyone." But that's not really a defense of attestation, it's just something to thank Apple for.