/**
 * Return the microsecond (0-999) from a UTC datetime string.
 *
 * - Returns zero-padded string for microsecond.
 * - Returns "" for invalid input.
 *
 * @param value ISO UTC datetime string (e.g., "2024-03-17T14:30:45.123Z")
 * @returns Microsecond (000-999) or "" on invalid input
 *
 * @example parseMicrosecondFromUtc("2024-03-17T14:30:45.123Z") // "123"
 * @example parseMicrosecondFromUtc("invalid") // ""
 */
export declare function parseMicrosecondFromUtc(value: string): string;