See https://twofactorauth.org/ https://twofactorauth.org/ . I thought there was an ongoing effort to add backup/restore steps to this informative site. Indeed,

See https://twofactorauth.org/ https://twofactorauth.org/ . I thought there was an ongoing effort to add backup/restore steps to this informative site. Indeed, I was recently locked out of some of my accounts: I used some "one-shot backup codes", but some sites didn't deliver them (and so, required involvment of admin/support by mail+phone).