Bip39. The passphrase is not picked through the predefined list of 2048 words – it could be any word or phrase you end up picking. BIP39 is often a structure implementation that lays out how copyright wallets develop the list of words (or "mnemonic codes") that make up a mnemonic https://thebookmarkking.com/story18721662/bip39-word-list-https-linktr-ee-bip39-bip-39-no-further-a-mystery