Guohui Deng enhanced performance telemetry in the mozilla/gecko-dev repository by introducing a new initiatorUrl field to ResourceTiming for HTML initiators, enabling more granular origin tracking for resource loads. Using JavaScript and web performance testing techniques, Guohui expanded test coverage to include document.write()-initiated resources, ensuring robust validation across diverse loading scenarios. To improve CI reliability, Guohui addressed a flaky test by refining cache handling and asynchronous operation resolution, and added a helper function to prevent test warnings. This work deepened observability for HTML resource timing and contributed to more stable, reliable browser testing and web development workflows.