Bip39 Checksum. Before everything you'll want to keep it Independently from your seed. Possessing your seed and also your passphrase in exactly the same spot defeats the goal of possessing a passphrase to begin with. BIP39 specifies a list of 2048 words from which the mnemonic phrase is picked out. https://thebookmarknight.com/story18637946/bip39-word-list-https-linktr-ee-bip39-not-known-factual-statements-about-bip39-list