Bip39 Algorithm. From this issue ahead the seed may be created on paper or spoken around phone and this opened up new, Bodily ways of backing up the seed (multiple paper copies in several places, strong copies on steel plates with extra defense from fire/flood and many others.). A standard https://thebookmarkking.com/story18954688/seed-phrase-generator-from-bitcoin-address-the-smart-trick-of-bip39-seed-phrase-that-nobody-is-discussing