Bip39 Standard. The passphrase is not chosen through the predefined list of 2048 words – it can be any word or phrase you decide on. BIP39 can be a style implementation that lays out how copyright wallets produce the list of words (or "mnemonic codes") which make up a mnemonic https://pukkabookmarks.com/story18894204/bip-39-https-linktr-ee-bip39-the-best-side-of-bip39