A merkle tree (also known as hash tree) can be used to verify any kind of data stored, handled and transferred in and between computers. It ensures that data blocks received from other peers in a peer-to-peer network are received undamaged and unaltered, and also can be used to check that the other peers do not lie and send fake blocks. Many system and systems we use nowadays implement it. Among them are git, bitcoin, btrfs, zfs, nix package manager and bitcoin.