/**
 * Collapse a list of time intervals into the minimum set of non-overlapping intervals.
 *
 * - List-form generalization of `intervalUnionTime`, which is pairwise only.
 * - Intervals are merged when they overlap or share an endpoint exactly (adjacent intervals
 *   ARE merged).
 * - Order of the input list does not matter; the result is sorted by start.
 * - Returns `[]` for an empty list.
 * - Returns `[]` when `intervals` is not an array, when any element is not a
 *   `{ start, end }` record of valid ISO PlainTime strings, or when any element has
 *   `start > end`.
 *
 * @param intervals array of `{ start, end }` records
 * @returns the minimum set of non-overlapping `{ start, end }` records, sorted by start, or `[]` on invalid input
 *
 * @example mergeIntervalsTime([{ start: "09:00:00", end: "12:00:00" }, { start: "11:00:00", end: "15:00:00" }]) // [{ start: "09:00:00", end: "15:00:00" }]
 * @example mergeIntervalsTime([]) // []
 * @example mergeIntervalsTime([{ start: "15:00:00", end: "09:00:00" }]) // []
 */
export declare function mergeIntervalsTime(intervals: Array<{
    start: string;
    end: string;
}>): Array<{
    start: string;
    end: string;
}>;