Bip39 Checksum. The passphrase isn't picked in the predefined list of 2048 words – it might be any word or phrase you end up picking. BIP39 specifies a list of 2048 words from which the mnemonic phrase is picked out. Each individual word signifies a variety inside a binary sequence, https://socialdosa.com/story9016252/bip39-word-list-https-linktr-ee-bip39-bip39-words-secrets