Firefox

Overview

Firefox is a cross-platform web browser for Windows, macOS, Linux, Android and iOS. It focuses on protecting user privacy, performance optimization and open source spirit, follows the Mozilla Manifesto, and is committed to providing a secure, fast and user-friendly browsing experience. Firefox does not rely on the Chromium engine, but uses its proprietary Quantum engine, emphasizing data privacy and independence.

• License: Mozilla Public License (MPL) 2.0.
• Latest version (as of May 2025): Firefox 126 (stable version, released in April 2025), supports Windows 10/11, macOS 10.15+, Linux and mobile devices.
• Supported languages: 97 regions (88 languages, as of April 2025)

Firefox provides privacy protection features (such as enhanced tracking protection), cross-device synchronization and a rich extension ecosystem, suitable for individual users, developers and privacy-conscious users.

History and Development

Firefox's origins can be traced back to 2002, when it was developed by the Mozilla community based on Netscape Navigator's open source code. The following is its main development history:

• 2002-2004:
  • In 2002, the Phoenix project was launched (later renamed Firebird, and then changed to Firefox), based on the Mozilla Application Suite.
  • In November 2004, Firefox 1.0 was released, supporting the bookmark toolbar and tabbed browsing, becoming one of the first browsers to popularize these features.
• 2000s:
  • Firefox 2.0 (2006) introduced session recovery and anti-phishing protection.
  • Firefox 3.0 (2008) optimized memory usage and supported Gecko engine improvements, becoming one of the most popular browsers.
  • Rapid release cycles (updated every 6-8 weeks) began in 2011, accelerating feature iteration.
• 2010s:
  • In 2017, Firefox Quantum (Firefox 57) was released, with a refactored engine and a multi-process architecture, which significantly improved speed and memory efficiency.
  • In 2019, Firefox 67.0 introduced protection against cryptocurrency mining and fingerprinting.
  • In May 2019, the expiration of the intermediate signing certificate caused the extension to be disabled, and Mozilla quickly fixed it through Mozilla Studies.
• 2020s:
  • In 2021, Firefox 85 removed Adobe Flash support and launched the Proton interface redesign (causing some users to criticize accessibility).
  • In March 2021, Firefox 87 introduced SmartBlock (full cookie protection) to prevent cross-site tracking.
  • In January 2022, HTTP/3 implementation issues caused service interruptions for several hours, which Mozilla quickly fixed.
  • In 2025, Firefox moved to the GitHub repository to enhance community participation.
  • In 2025, Mozilla introduced new terms of use, sparking privacy controversy, but clarified that it does not involve AI or data sales.
  • Community and Ecosystem:
  • Firefox is developed by the Mozilla Foundation (non-profit organization) and Mozilla Corporation, following the Mozilla Manifesto.
  • Supports 97 language localizations through the Pontoon platform (as of April 2025).
  • The community contributes extensions and code through GitHub and addons.mozilla.org.

Main Features

Firefox's features revolve around privacy, performance, and customizability. Here are its core features:

1. Privacy Protection:
   • Enhanced Tracking Protection: Automatically blocks third-party trackers, social media trackers, cryptocurrency mining scripts, and fingerprint tracking scripts.
   • SmartBlock (Full Cookie Protection): Isolate cookies and data for each site to prevent cross-site tracking.
   • Private Browsing Mode: No browsing history or cookies are saved, and one-click opening is supported (right-click link -> New Private Window).
   • DNS over HTTPS (DoH): Support for encrypted DNS queries, enabled via the network.trr setting (mode 0-3), with privacy protocol protection provided by Cloudflare.
2. Performance optimization:
   • Quantum engine: Multi-process architecture reduces memory usage and optimizes multi-tab browsing.
   • Support for HTTP/2 and HTTP/3 (although HTTP/3 issues have occurred in 2022).
   • Fast page loading, tracker blocking further improves performance.
3. Cross-device synchronization:
   • Mozilla account syncs bookmarks, passwords, history, and open tabs.
   • Support for desktop and mobile devices, with simple settings (Menu -> Login Sync).
4. Customizability:
   • Support for thousands of free themes and extensions (such as HTTPS Everywhere, uBlock Origin).
   • Advanced settings (such as DoH, interface options) can be adjusted through about:config.
   • The new tab page can be customized to include recommended content or fixed tabs (such as mailbox).
5. Address bar and search:
   • Unified search and address bar, providing bookmarks, history and popular search suggestions.
   • Google search is used by default, and can be changed to other engines (such as Bing, DuckDuckGo).
6. Extension ecosystem:
   • Extensions such as Firefox Relay (anonymous mailbox) and Firefox Monitor (data leakage monitoring) are provided through addons.mozilla.org.
   • Support WebExtensions API and compatible with Chrome extensions.
7. Additional products:
   • Firefox Monitor: free service, monitoring data leakage.
   • Mozilla VPN: paid VPN service, encrypting network activities, protecting IP addresses.
   • Firefox Relay: provides anonymous mailboxes and phone masks to prevent spam.
8. Localization and accessibility:
   • Support 97 regions (88 languages), using Project Fluent to optimize translation.
   • Provide screen reader support, but the Proton interface has caused some accessibility controversy.

Advantages and limitations

Advantages

• Privacy first:
  • Automatically blocks trackers, fingerprinting scripts, and cryptocurrency mining to protect user data.
  • Does not sell user data, in contrast to Chrome and Safari.
• Open source and transparency:
  • Follows MPL 2.0, code is open, and will move to GitHub in 2025 to enhance community participation.
  • Supported by the non-profit Mozilla Foundation, it follows the principle of user priority.
• Performance and speed:
  • The Quantum engine optimizes multi-tab performance, and its speed is comparable to that of mainstream browsers.
  • Tracker blocking improves page loading speed.

• Customizability:

  • Rich extension and theme support to meet personalized needs.
  • Flexible settings (such as about:config) are suitable for advanced users.

• Cross-platform support:

  • Compatible with desktop and mobile devices, and the synchronization function is seamless.

Limitations

• Low market share:
  • Global market share in 2022 is only 3%, far lower than Chrome and Safari.
  • Mozilla laid off 25% of its employees in 2020, raising concerns about future development.
• Privacy terms controversy:
  • New terms of use in 2025 (granting Mozilla data use permission) raise privacy concerns, although Mozilla clarified that it does not involve data sales or AI.
• Accessibility issues:
  • The Proton interface (2021) has caused some users to criticize screen reader support, which has not been fully resolved as of 2024.
• Extension compatibility:
  • The expiration of the certificate in 2019 caused the extension to be disabled, affecting the user experience.
  • Some Chrome extensions may need to be adjusted to be compatible with Firefox.
• Resource usage:
  • Although Quantum optimizes memory, some situations (such as multiple tabs or complex extensions) may still occupy more resources.

Summary

Firefox is a web browser developed by the Mozilla Foundation and Mozilla Corporation with privacy, speed and open source at its core. Its Quantum engine, enhanced tracking protection and cross-device synchronization make it competitive with Chrome, Safari and others in terms of performance and user experience. The migration to GitHub in 2025 and the rich extension ecosystem further enhance community participation and feature expansion. Despite the challenges posed by low market share and controversial privacy terms, Firefox still attracts privacy-conscious users and developers with its independence and user-first philosophy.