Systems

The major architectural subsystems that make up Gecko. Most of these are not deployed independently; they layer together to produce the running browser. They're documented here separately because each is large enough to onboard new contributors on its own.

Pages

• Process model — parent / content / GPU / Socket / RDD / Utility processes
• IPC and IPDL — the actor framework
• XPCOM and component framework — refcounting, services, IDL, threading
• DOM — every Web platform implementation
• Layout — the frame tree, reflow, painting
• Graphics and WebRender — gfx/, compositor, WebRender
• SpiderMonkey — the JS engine
• Networking — netwerk/, HTTP, sockets, cache, cookies
• Style and Stylo — Rust CSS engine
• Accessibility — accessible/
• Editor — editor/
• Image — image decoders and pipeline
• DevTools — built-in developer tooling
• Automation (Marionette / WebDriver BiDi / CDP)
• Storage and IndexedDB
• Build system — mach, mozbuild, taskcluster