MultiBit is dead - https://multibit.org

It was a popular lightweight wallet that came in two flavours ("Classic" and "HD"), but after it got sold to KeepKey it went downhill until it was so old and outdated that they couldn't be bothered developing it any more to keep up with changes to Bitcoin and they made the decision to kill it.

Do NOT use either of these wallets unless you want your coins to get stuck in low fee transactions or "corrupt" wallets