/**
 * Given an unindexed ICU string, extracts all the _gt_ variables and an indexed mapping of the variable to the values
 *
 * extractVars('Hello {_gt_, select, other {World}}') => { _gt_1: 'World' }
 *
 * @param {string} icuString - The ICU string to extract variables from.
 * @returns {Record<string, string>} A mapping of the variable to the value.
 */
export declare function extractVars(icuString: string): Record<string, string>;