(Scythian? cython…) Rust had packaging, great tooling for testing and docs, great FFI for Python, AND could be compiled to wasm. And a much better story for refactoring and maintaining code in the long term, which was starting to become a strain in the Python parts of sourmash

Nowadays sourmash does run emscripten too (via pyodide), and if you have a lot of C/C++ code it makes sense to go with it. But POSIX in the browser also leads to some weirdness, because they are different environments.