Ubuntu 25.10’s transition to using Rust Coreutils in place of GNU Coreutils has uncovered a few performance issues so far with the Rust version being slower than the C-based GNU Coreutils. Fortunately there still are a few weeks to go until Ubuntu 25.10 releases as stable and upstream developers are working to address these performance gaps.
They don’t need to use semantic versioning. I doubt coreutils itself uses it, though I admit I haven’t checked. Actually I think semantic versioning is less popular in practice than it looks like.
For a set of tools to that completely replaces another one, announcing a 1.0 version would be a message that the developers think the project has actually reached its initial goals. “0.2” does not.