There are many module level containers with constants. By replacing the mutable containers with immutable variants (e.g. replace a set with a frozenset or a list with a tuple) we improve performance ...
uv -vvv python upgrade 3.14 DEBUG uv 0.8.19 (fc7c2f8b5 2025-09-19) warning: `uv python upgrade` is experimental and may change without warning. Pass `--preview-features python-upgrade` to disable this ...