u/irrelevantusername24

>Other browsers Rebans confirmed as vulnerable include Brave, Opera, Vivaldi, and Arc. Both Firefox and Safari are unaffected because they don’t support the browser-fetching feature.

There's a lot to this, and I understand the complexity and code far less than... well, I'll say I understand it less than I should need to in order to understand things as well as I do.

Anyway

This reminds me of a really nifty graphic of a timeline of browser heritage on a recent Mozilla blog post, which pointed out to me for the first time that the Tor browser is built on the Gecko engine. Pretty neat. Here's that blog post:

Competition, Innovation, and the Future of the Web – Why Independent Browser Engines Matter by Andrew Overholt 23 March 2026