zammad/app/frontend/shared/graphql/mutations/login.graphql

mutation login($input: LoginInput!) {
  login(input: $input) {
    session {
      ...session
    }
    errors {
      ...errors
    }
    twoFactorRequired {
      availableTwoFactorAuthenticationMethods
      defaultTwoFactorAuthenticationMethod
      recoveryCodesAvailable
    }
  }
}