Currently no major browser has significant components implemented in a safe language like Rust. And while there are some efforts towards granular parallelism in

Currently no major browser has significant components implemented in a safe language like Rust. And while there are some efforts towards granular parallelism in existing major browsers, none really took a "start from scratch and get it right" approach like the Servo components that Quantum intends to adopt (and that's very noticeable in Servo perf). So on both of those aspects, the plan here is to go significantly further than any existing major browser.