Entirely mechanical, produced by `ruff check --fix --select F401,F541,E713`
and reviewed rather than taken on faith: deleting an import is only safe if
nothing imports it for its side effects or re-exports it. None of the 19
removed names is referenced anywhere in its file, none appears in any string
literal, and none of the touched files uses eval, exec, globals() or
__import__, so there is no dynamic lookup that could reach them.
Markus Hilger
644843b892