Advanced and experimental features

Configuration Editor for Firefox

The Configuration Editor (about:config page) lets you view, change, or reset advanced preference settings in Firefox. Learn more.

How to opt out of studies

Fingerprinting Protection is an experimental feature that is under heavy development in Firefox.

Learn about a workaround to activate compact mode, if you need to. This feature isn't supported and we still recommend using normal mode.

Add Container tabs to Firefox with the Multi-Account Containers add-on, to separate your work and personal browsing.

Learn about Firefox Nightly's error collection policy.

Firefox Sync allows you to sync your preference settings across all your Firefox Desktop devices. Learn more.

Firefox 66 introduced DOM events changes for compatibility with legacy content. Learn more.

Network administrators may configure their networks to modify DNS requests for the following special-purpose domain, called a ''canary domain''.

This page explains the technical documentation on how to control media in Firefox by using the Media Session API.

Use Windows single sign-on (SSO) to log in to Microsoft, work, and school accounts with credentials from your Windows 10 or 11 operating system.

Two types of advanced Firefox customization options, about:config and userChrome.css modifications, are not recommended. Learn more.