She wants to learn kernels, and she wants to learn Rust. There are no extant kernels written in Rust, so she's making one. Contributing to an existing program

She wants to learn kernels, and she wants to learn Rust. There are no extant kernels written in Rust, so she's making one. Contributing to an existing program (positively or negatively) may be more valuable, but I would say this project is more ambitious. Also, if her goal is knowledge of the system, it's more instructive to build from the ground up rather than start with a system where you can always take parts of it for granted.