Explore the future of web browsing in this 22-minute Web Summit talk, where Mozilla's Mark Mayo delves into the challenges and innovations of modern browser design. Learn about the delicate balance between performance and memory usage in multi-tab browsing, and discover how a new API is revolutionizing the add-ons ecosystem. Gain insights into Firefox's latest developments, including multithreading improvements, the implementation of Rust, and a redesigned user interface. Understand the reasons behind Firefox's long development process and the significant benefits it brings to users. From internal mascots to jet engines, this talk covers a wide range of topics that showcase Mozilla's commitment to reinventing the web browser for contemporary computing needs.