/**
 * Copyright IBM Corp. 2025
 *
 * This source code is licensed under the Apache-2.0 license found in the
 * LICENSE file in the root directory of this source tree.
 */
/**
 * Returns the provided locale if it is supported by the runtime's
 * `Intl.NumberFormat`, otherwise falls back to the provided fallback
 * (or `'en-US'` when no fallback is given).
 */
export declare function getSupportedLocale(locale: string | undefined, fallback?: string): string;