Matt Wenner upgraded the calibration data retrieval API in the quantumlib/Cirq repository, replacing a legacy workflow with a modernized method that streamlines how calibration data is fetched for specific jobs. He removed outdated documentation to clarify the new retrieval process and added comprehensive unit tests using Python, focusing on mocking techniques to ensure correctness and prevent regressions. This work improved maintainability and test coverage, reducing support overhead and enabling safer future API migrations. By aligning the API with current best practices, Matt’s contributions facilitated faster onboarding for new developers and supported the ongoing deprecation of legacy workflows within the project.