April 24, 2026
Firefox + Brave: adblock frenemies
Firefox Has Integrated Brave's Adblock Engine
Mozilla borrows Brave's blocker; uBlock fans cheer while purists cry 'Eich betrayal'
TLDR: Firefox quietly added Brave’s ad‑block engine under the hood, disabled by default but testable via settings. The community is split between excitement for potential uBlock Origin benefits, fears Mozilla could later sideline powerful ad‑block extensions, and drama over Mozilla–Brave history—making this a big moment for how browsers handle ads and privacy
Firefox quietly slipped Brave’s ad‑blocking engine into version 149—off by default, no buttons, just a hidden switch—and the comments lit up. For the unfamiliar: an ad‑block engine is the bit that stops ads and trackers; this one comes from Brave and speaks uBlock‑style filter lists. One camp immediately asked, will this turbocharge beloved add‑on uBlock Origin? Another camp side‑eyed Mozilla: is this a sneaky first step to phasing out powerful extensions later and herding users toward “acceptable ads”? Meanwhile, the soap‑opera crowd reopened old wounds, calling it a twist after Mozilla’s split with Brave’s co‑founder Brendan Eich.
There’s pride and pettiness in equal measure. Brave fans flexed that they jumped ship ages ago and love Brave’s little “scriptlets,” while Firefox diehards grumbled that it took a rival—and Rust!—to hand Mozilla a modern blocker. Waterfox, a Firefox cousin, has already adopted it, fanning the “Spider‑Man pointing meme” jokes: Brave and Firefox, same vibes. Technically, this is a prototype landed via Bug 2013888; you can enable it in the advanced settings and load EasyList/EasyPrivacy to see ads vanish into empty frames. Nothing’s being forced, but the crowd smells foreshadowing, and the vibes are equal parts hope, paranoia, and popcorn
Key Points
- •Firefox 149 quietly includes Brave’s adblock-rust engine as a disabled-by-default prototype with no UI or bundled lists.
- •The integration was added via Bugzilla Bug 2013888 by Mozilla engineer Benjamin VanderSloot.
- •Adblock-rust, written in Rust and licensed under MPL-2.0, supports network request blocking, cosmetic filtering, and uBlock Origin–compatible syntax.
- •Waterfox has adopted adblock-rust, building on Firefox’s implementation.
- •The article details how to enable and test the prototype in about:config using EasyList and EasyPrivacy, with Yahoo used as a test site.