ERC-4337

Co-authored by Vitalik Buterin, Yoav Weiss, Kristof Gazso, Dror Tirosh, Shahaf Nacson and Tjaden Hess, ERC-4337 introduces account abstraction without any modifications to the core protocol. It achieves so by replicating the functionality of the transactions mempool in a higher-level system. However, instead of transactions, users send UserOperation objects to Ethereum nodes, and they package a set of these objects into a single transaction that gets included in the Ethereum chain.