Firefox Source Docs

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Overview

A Glossary of Common Terms
A Quick Guide to Mozilla Applications

Getting Started

Getting Set Up To Work On The Firefox Codebase

Working On Firefox

Working on Firefox
Bug Handling
Firefox Crash Reporting

Firefox User Guide

Source Code Documentation

The Firefox Build System

Mach
Pushing to Try
Build System
Firefox CI and Taskgraph
Managing Documentation
Vendoring Third Party Components

Testing & Test Infrastructure

Automated Testing
Understanding Treeherder Results
Sheriffed intermittent failures
Turning on Firefox tests for a new configuration
Avoiding intermittent tests
Debugging Intermittent Test Failures
Testing Policy
Configuration Changes
Browser chrome mochitests
Chrome Tests
geckodriver
Test Verification
WebRender Tests
Mochitest
XPCShell tests
TPS
web-platform-tests
GTest
Fuzzing
Sanitizer
Performance Testing
Code coverage
Testing & Debugging Rust Code

AI Agent Tools

AI Agent Tools for Firefox Development

Releases & Updates

Mozilla Update Infrastructure
Watershed Updates
Desupport Updates
Update Verify

Localization & Internationalization

Internationalization
Localization

Firefox and Python

mozbase
Using third-party Python packages

Metrics Collected in Firefox

Firefox metrics

Firefox Source Docs

Style system (CSS) & Layout
Layout Code Reviewer Checklist
Report an issue / View page source

Layout Code Reviewer Checklist

General

Follow the general reviewer checklist.

Security issues

Watch for raw pointers that may have their data deleted out from under them