GitHub.com users who set up two-factor authentication will see a prompt after 28 days, asking them to perform 2FA and confirm their second factor settings. This prompt helps avoid account lockout due to misconfigured authenticator applications (TOTP apps), especially those that failed to save the TOTP secret after validating it during set up.
This prompt appears in existing sessions if you haven't already performed 2FA as part of a sudo prompt or signing in on another device. If you find that you can't perform 2FA, you'll be presented with a shortcut that allows you to reset your 2FA setup.
All users that enable 2FA will be eligible for this prompt, including users required to enable it by their organization or GitHub itself.
To learn more about two-factor authentication, see "Configuring two-factor authentication".