parity --help has description below:
--chain=[CHAIN] Specify the blockchain type. CHAIN may be either a JSON chain specification file or olympic, frontier, homestead, mainnet, morden, ropsten, classic, expanse, musicoin, ellaism, testnet, kovan or dev. (default: foundation)
I really can't find what foundation means. And it seems having no difference with mainnet if you check the block on etherscan. So, dose anyone knows what's the difference between "foundation" and "mainnet" ? Branch of thanks!