There are many browsers, but only three widely-used engines. We maintain one of those engines - Gecko. Here's why we feel that browser engine diversity is essential for the future of the web https://blog.mozilla.org/netpolicy/2026/03/23/competition-innovation-and-the-future-of-the-web/
Competition, Innovation, and the Future of the Web – Why Independent Browser Engines Matter – Open Policy & Advocacy

Gecko matters because it ensures there’s an independent voice shaping how the internet evolves. Without Gecko, the landscape would be dominated by Apple and Google alone. Is that really the ...

Open Policy & Advocacy
@firefoxwebdevs belief me, I don't miss Trident. 😜 It's sad that Presto is dead, though.
@xela we miss it too! Quite a few Presto engineers ended up at Mozilla.