Also just so you know, Brave isn't "written" in Rust alone, it is a big software with a lot of parts, including but not limited to a rendering engine, a JS VM and a WASM engine.
The Rust part at most (unconfirmed) would be the glue that connects them together, and I doubt that's where the bottleneck is for most browsers.
>The new algorithm with optimised set of rules is 69x faster on average than the current engine.