metamask-extension/app/scripts/controllers/network/contract-addresses.js

const SINGLE_CALL_BALANCES_ADDRESS = '0xb1f8e55c7f64d203c1400b9d8555d050f94adf39'
const SINGLE_CALL_BALANCES_ADDRESS_RINKEBY = '0x9f510b19f1ad66f0dcf6e45559fab0d6752c1db7'
const SINGLE_CALL_BALANCES_ADDRESS_ROPSTEN = '0xb8e671734ce5c8d7dfbbea5574fa4cf39f7a54a4'
const SINGLE_CALL_BALANCES_ADDRESS_KOVAN = '0xb1d3fbb2f83aecd196f474c16ca5d9cffa0d0ffc'

module.exports = {
  SINGLE_CALL_BALANCES_ADDRESS,
  SINGLE_CALL_BALANCES_ADDRESS_RINKEBY,
  SINGLE_CALL_BALANCES_ADDRESS_ROPSTEN,
  SINGLE_CALL_BALANCES_ADDRESS_KOVAN,
}