I rewrote the mutation testing tool that I created for Bitcoin Core. It was originally written in Python but I got some issues that made me to rewrite it in Rust. It contains the same features as the original tool has:

- Generate mutants only for code touched in specific branches (useful for testing PRs)

- Skip useless mutants (comments, LogPrintf statements, etc.)

- One mutant per line mode for faster analysis

- Support for functional and unit test mutation

- Coverage-guided mutation testing

Check it out: https://github.com/brunoerg/bcore-mutation

We successfully migrated corecheck to use this new tool recently.