This contract is used to handle the weekly distribution of EPS to veCRV holders within the Curve DAO.
Each week a new snapshot is generated according to a publicly available script on Github. The proposalAuthority (the Ellipsis team) submits the hash of the proof on-chain, and then the reviewAuthority (the Curve team) accepts or rejects it. Once the proof is accepted, the receivers may begin to claim immediately.
You can view source for MerkleDistributor on Github.