Bip39 passphrase github https://telegra.ph/Producing-Custom-Bitcoin-Addresses-A-Take-A-Look-At-BIP39-Strategies-06-28 Regardless that it uses BIP32 system you can even now import BIP39 seeds into Electrum wallet. Also apart from BIp32 There's BIP44 version which some wallet use with the generation of seeds. Because of the cryptographic style of BIP-39, a weak passphrase isn't going to... https://mysocialname.com/story5566957/bip39-wordlist-english-github-helping-the-others-realize-the-advantages-of-bip39-passphrase-https-linktr-ee-bip39