Worked on the localstack/moto repository to address a nuanced issue in S3 GetObject 304 Not Modified responses, focusing on improving the fidelity of cloud service mocking for integration tests. Using Python and leveraging skills in API implementation and backend development, implemented a fix that ensures ETag headers are correctly returned while omitting content-related headers, closely matching AWS S3 behavior. This adjustment reduced edge-case test failures and enhanced the reliability of S3-based workflows for developers relying on localstack/moto. The work contributed to more accurate API simulations, supporting robust and dependable testing environments for cloud-native applications that interact with S3.