Why are devices listed when I use Account Key to sign in?
The Yahoo account key sends a notification that you accept on your mobile device with the ability to insert to access your account, instead of using a password. You can associate several devices per account to get this notification.
During a security review, you will see a list of all associated devices that can receive this notification so you can review and control which devices can grant access to your account.
We recommend that you disconnect unknown, old or unused devices by clicking Logout next to the device. You can also review your recent activity at any time to review this information.