June 2025: Delivered targeted experimentation capabilities and measurement enhancements across two Mozilla repositories, enabling precise segmentation, controlled experiments, and end-to-end metrics that inform product decisions. Key outcomes include RAM-based targeting and sponsor-based rules for Firefox Experiments, plus a TOML-driven de-duplication configuration for search results with enrollment period and exposure signaling. These changes establish a scalable foundation for data-driven optimization, improving relevance of Firefox experiences and the reliability of engagement metrics.

May 2025 monthly summary for mozilla/metric-hub: Key feature delivered was an experiment configuration for Address Bar Updates and Launch Holds. Introduced a new TOML configuration that defines user segments, experiment metrics for default search engine changes and searches with non-default engines, and data sources including Glean events and client daily data. This enables controlled experimentation and robust telemetry for feature validation. Committed as b5394e2b73150d4d97f04ee4742d3ee7b3378ee1 (Create address-bar-update-launch-hold.toml (#902)).