lol amazon supports U2F keys, but only for AWS (retail uses a different MFA system, and you can have both on at once, in which case it's never clear which TOTP code it's prompting for), and you can only have one U2F key per account??? the fuck?????
And retail let's you add TOTP authenticators, but not delete them without disabling 2FA entirely and wiping them all. Them again Twitter also supports only one U2F key.
