2FA (BitBox01) description

Use a mobile phone as a large screen for securely verifying transactions and receiving addresses created by the Digital Bitbox (BitBox01) hardware wallet.

This app works only with the now discontinued BitBox01 device.
Check out the website for more details: https://shiftcrypto.ch/bitbox01/.

The code is open source and available here: https://github.com/digitalbitbox/2FA-app.