Why does the BIP44 derivation path generate the same address in MetaMask as the Ledger Live derivation path?

Question

Looking at MetaMask's source code (commit 99ed42), I can see that the derivation paths for Ledger Live and BIP44 differ slightly:

const LEDGER_LIVE_PATH = `m/44'/60'/0'/0/0`;
const BIP44_PATH = `m/44'/60'/0'/0`;

Ledger Live has an extra 0.

So why do these two derivation paths generate the same address in MetaMask?

I'm getting the same address when I choose either path in the dropdown!

Answer 1

That extra zero indicates the key pair number derived from the master seed(commonly referred to as address_index). You can read more about it here https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki. The derivation path means:

m’ / purpose’ / coin_type’ / account’ / change / address_index

As you can see the last is address_index which is usually appended at the last of the master derivation path, in your case at

const BIP44_PATH = `m/44'/60'/0'/0`;

This is to generate various accounts (when you click "Generate a New Account" in MetaMask) from the same mnemonic. So subsequent address paths would be:

m/44'/60'/0'/0/0  //First Account or key-pair
m/44'/60'/0'/0/1  //Second Account or key-pair
m/44'/60'/0'/0/2  //Third Account or key-pair

For the ledger, the first account is usually used for doing transactions, so the address with 0 for the first account is already hard-coded in the string.