Create multiple backups of the unedited wallet.dat file on offline, air-gapped USB drives.
An old wallet.dat file is essentially a database of your Bitcoin keys and transaction history, often dating back to the early days of cryptocurrency. If you have found one, it may contain private keys for Bitcoin or various forks (like Bitcoin Cash or Bitcoin Gold). Essential Safety First old walletdat exclusive
A pre-generated batch of 100 unused private keys meant for future transactions and change addresses. Create multiple backups of the unedited wallet
An in this context implies scarcity. It was likely: old walletdat exclusive
