In this talk, the speaker discussed the power usage of Firefox and the importance of understanding and optimizing power usage for a better user experience and to promote sustainability. They explained how Firefox uses power by using CPU and GPU time and discussed the ways in which power is wasted, such as excessive wake-ups and background processes. They shared various tools and techniques for understanding and troubleshooting power usage locally, including the Firefox task manager and the Firefox profiler. They also discussed the use of telemetry data to understand power usage across all users and gave examples of how this data can be used to estimate carbon footprint, verify the impact of bug fixes, and identify areas for improvement. The speaker described various bug fixes that have been made to reduce power usage and shared ideas for future improvements, such as optimizing background tabs and reducing unnecessary animations. They also mentioned the idea of experimenting with different power-saving configurations, such as limiting the refresh rate and blocking videos that are not being actively viewed. The speaker emphasized the importance of profiling to accurately identify and address power usage issues and encouraged further questions and discussions on the topic.