/**
 * Column-letter adornment (`A`, `B`, …) rendered in the header title container
 * next to the title, in a dimmed colour. Subscribes to the shared A1 position
 * context so the letters stay in sync on reorder/visibility changes. Hidden from
 * assistive tech (the letter is editor sugar, not column meaning) and blank for
 * columns with no position (utility/grouping/hidden).
 */
export declare function GridFormulaColumnHeaderLetter({
  field
}: {
  field: string;
}): import("react").JSX.Element | null;