This Custodial Qualification was an opportunity for ATRI holders to verify their identity to determine the amount of ATRI held and to confirm that they will be participating in the upcoming claim for a fixed amount of third-party SAND tokens.
If a holder's ATRI was visible on-chain for the snapshot on April 18, 2022, they did not need to complete the Custodial Qualification, they would have simply Opted-in. This would have been be verified using the eligibility checker with the result of "eligible".