This is an Authentication Extension, which allows you to authenticate with a second factor if possession against privacyIDEA.
privacyIDEA is a system to manage authentication devices like OTP-Tokens, Yubikeys, Google Authenticator, FreeOTP, One Time Passwords via Email and via SMS and many more.
The great thing about privacyIDEA is, that you do not need to trust a service provider, since you can run your own privacyIDEA installation in your network or datacenter. Your server, your keys, your data and your control.
You can setup one privacyIDEA system to manage all authentication devices of all your users and customers. Several TYPO3 installations can authenticate against this centrally manages privacyIDEA installation under your control.