I'm pretty sure they've existed since before TOTP was an option (I created mine in 2012, which was before I used any two-factor at least), but you have to go in

I'm pretty sure they've existed since before TOTP was an option (I created mine in 2012, which was before I used any two-factor at least), but you have to go into your account settings to enable them: https://myaccount.google.com/security https://myaccount.google.com/security "Backup codes" is in the "How you sign in to Google" section.