Rakan Rustomhamoury enhanced reliability and testing workflows across the goldmansachs/legend-engine and finos/legend-studio repositories. He focused on backend and UI development using Java, TypeScript, and React, addressing data integrity issues in the Relational Store by implementing robust duplicate column mapping checks and comprehensive tests. In Legend Studio, Rakan streamlined the testing workflow by introducing diff view tables for non-JSON objects and an 'accept changes' feature, making test result updates more efficient. He also improved the EqualToAssertFailViewer to correctly handle primitive types as native values, reducing false warnings and accelerating test maintenance for more accurate validation.