Comment by VorpalWay

Native code usually refers to code which is compiled to machine code (for the CPU it will run on) ahead of time, as opposed to code running in a byte code VM (possibly with JIT).

I would consider all of C, C++, Zig, Rust, Fortran etc to produce native binaries. While things like Cython exist, that wasn't what was used here (and for various reasons would likely still have more overhead than those I mentioned).