Show HN: Adblock-rust Manager – Firefox extension to enable the Brave ad blocker

A Firefox extension that enables and manages Firefox's built-in adblock-rust engine — Brave's open-source, Rust-based ad and tracker blocking engine, quietly shipped in Firefox 149.

In March 2026, Firefox 149 silently shipped adblock-rust — the same Rust-based content blocking engine that powers Brave's native ad blocker. It supports network request blocking, cosmetic filtering, and is fully compatible with uBlock Origin filter list syntax.

Mozilla shipped it disabled by default, with no user interface and no mention in the release notes. It is controlled exclusively by two about:config preferences:

• privacy.trackingprotection.content.protection.enabled: Enables/disables the engine
• privacy.trackingprotection.content.protection.test_list_urls: Pipe-separated list of filter list URLs

This extension gives you a proper UI to manage both.

Key Features:

• One-click ETP toggle: Disable Firefox's built-in Enhanced Tracking Protection so adblock-rust handles blocking instead.
• Guided setup: Step-by-step instructions for the about:config prefs that can't be set programmatically.
• Filter list manager: Add, remove, and reorder filter lists automatically.
• 8 preset lists: Quick-add popular lists including EasyList, EasyPrivacy, uBO Filters, and AdGuard.
• Persistent state: Settings survive browser restarts.

Technical Constraints: Standard WebExtensions cannot write arbitrary about:config preferences. That requires a Mozilla-signed privileged add-on. The current approach uses standard MV3 WebExtension APIs and guides the user through a one-time ~30 second manual setup for the core preferences.

Installation: Users can load it as a temporary add-on via about:debugging or install it permanently by setting xpinstall.signatures.required to false in about:config and installing from file.