/**
 * Return the symmetric difference of two UTC intervals — time covered by exactly one interval.
 *
 * - Uses `Temporal.Instant.compare` for comparison.
 * - Returns `[]` when intervals are identical or both invalid.
 * - Returns `[{ start, end }]` when one interval fully contains the other.
 * - Returns `[{ start, end }, { start, end }]` when intervals partially overlap.
 * - Returns `[]` if either interval is invalid (`start > end`).
 * - Returns `[]` on invalid input (wrong type, malformed strings, leap seconds).
 *
 * @param aStart ISO 8601 UTC datetime string for the first interval start
 * @param aEnd ISO 8601 UTC datetime string for the first interval end
 * @param bStart ISO 8601 UTC datetime string for the second interval start
 * @param bEnd ISO 8601 UTC datetime string for the second interval end
 * @returns array of `{ start, end }` records representing the symmetric difference, or `[]` on invalid input
 *
 * @example intervalXorUtc("2024-01-01T09:00:00Z", "2024-06-30T12:00:00Z", "2024-04-01T11:00:00Z", "2024-12-31T17:00:00Z") // [{ start: "2024-01-01T09:00:00Z", end: "2024-03-31T17:00:00Z" }, { start: "2024-06-30T12:00:01Z", end: "2024-12-31T17:00:00Z" }]
 * @example intervalXorUtc("2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z", "2024-04-01T11:00:00Z", "2024-06-30T12:00:00Z") // [{ start: "2024-01-01T09:00:00Z", end: "2024-03-31T17:00:00Z" }, { start: "2024-06-30T12:00:01Z", end: "2024-12-31T17:00:00Z" }]
 * @example intervalXorUtc("2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z", "2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z") // []
 * @example intervalXorUtc("invalid", "2024-06-30T12:00:00Z", "2024-07-01T13:00:00Z", "2024-12-31T17:00:00Z") // []
 */
export declare function intervalXorUtc(aStart: string, aEnd: string, bStart: string, bEnd: string): Array<{
    start: string;
    end: string;
}>;