Bip39. The passphrase is just not selected through the predefined list of 2048 words – it can be any word or phrase you decide on. BIP39 is often a design implementation that lays out how copyright wallets make the set of words (or "mnemonic codes") which make up a mnemonic https://bookmarkcolumn.com/story19384358/bip39-generator-https-linktr-ee-bip39-5-essential-elements-for-bip-39