/** A day of the week, as `Date#getDay()` counts: 0 is Sunday, 1 is Monday. */
export type Weekday = 0 | 1 | 2 | 3 | 4 | 5 | 6;
/**
 * The locale's first day of the week, falling back to Monday where `getWeekInfo` is missing:
 * it is Baseline only since July 2026 (Chrome 130, Firefox 153, Safari 17).
 */
export declare function localeWeekStart(locale: string | undefined): Weekday;