interface AuthenticatorAttestationResponseFuture
extends AuthenticatorAttestationResponse
AuthenticatorAttestationResponse in TypeScript's DOM lib is outdated (up through v3.9.7). Maintain an augmented version here so we can implement additional properties as the WebAuthn spec evolves.
See https://www.w3.org/TR/webauthn-2/#iface-authenticatorattestationresponse
Properties marked optional are not supported in all browsers.