Its interface and mechanism are similar to stdlib’s gb_trees, with a notable difference that all trees are also Merkle trees. What follows, values are stored only on leaf nodes. Having an agreement only on the root hash of a tree, one can prove that a particular key and value combination belongs to the tree.
Applications include storing states for blockchains — see Tendermint’s Application Blockchain Interface which represents application state as Merkle root hash ( https://github.com/tendermint/abci ).
Snapshot of the documentation for 0.1.0 release has been put on IPFS: