Bip39 Passphrase. You would probably then do a basic recovery with a command like the a person under. (This command makes use of a sample wallet file bunlded with BTCRecover) Any individual else who discovers the phrase can steal the bitcoins. It has to be held magic formula, for example https://ilovebookmark.com/story19353934/bip-39-https-linktr-ee-bip39-bip39-wallet-can-be-fun-for-anyone