Firefox Fission: How Site Isolation Works and Why It Matters

Firefox utilizes the Gecko rendering engine, developed since 1997, to parse HTML and CSS, create the DOM, and render layouts. This engine integrates with JavaScript APIs and WebAssembly to ensure web standards diversity. Additionally, the Fission project implements Site Isolation, evolving from the e10s architecture. Fission ensures each site origin, including separate subdomains and iframes, operates within its own isolated process, fundamentally changing how Firefox handles process separation to enhance security and stability across the browser.