In relation to the pre-commit PR #628. A while ago I started a list of ruff rules that need to be ignored in the future. With the latest version of ruff (0.12) - if we add it - some of the preview rules became active in the standard set (e.g., UP045, RUF041) but shouldn't be applied to typing_extensions.
Some of the rules I've added in this PR are still in preview, I think it makes sense to add them pro-actively.

Possibly we want RUF023 (sorted slots) only on a per line ignore.

    "RUF012",  # Use ClassVar for mutables (active now)
    "RUF022",  # Unsorted __all__  (active now)
    "RUF023",  # Unsorted __slots__ (active now)
    "RUF031",  # parentheses for tuples in subscripts (preview)
    "RUF041",  # nested Literal (active now)
    "RUF036",  # None not at end of Union (preview)
    "B903",  # Use dataclass / namedtuple  (preview)