fn bulk_folders<'a>(files: impl Iterator<Item = &'a str>) -> Vec<String>Expand description
Where files gone many at once were, said shortly, by their place in the store (“” for its own top): the deepest folder that holds four in five of them; else the few folders below it, three at most, that hold four in five of them together; else that folder, which holds them all. For thousands of files in hundreds of folders (a tool’s run folders), the folder above them all, never three of them picked at random (review of 17 October 2026, L5).