2FA setup only offers a QR code, not the secret key—so I can't set it up

What I Wanted to Do

Set up 2FA using a TOTP client that uses textual secret keys.

What Happened Instead

I was only offered a QR code for setup, so I couldn’t finish.

Reproduction Steps

  • Begin “Enable 2FA” flow
  • Select “Authorization and Publishing” level
  • Confirm password
  • Presented with QR code, but not secret key text

Details

I have a TOTP client that requires me to enter the secret key string as text. This would also be applicable if I had a smartphone with a broken camera.

Sites such as Github present both a QR code and a textual key.

Platform Info

Latest Firefox ESR browser.