Why isn't this global declaration file merging with other types?

[tropic orchid]

Here's a relevant excerpt:

/// <reference types="jquery" />
declare global {

    interface Math {
        /**
         * Returns the given number clamped to the specified bounds. Does not modify the original.
         * @param num The number to clamp. May be an actual number or a numerical string.
         * @param min The lower bound of the number.
         * @param max The upper bound of the number.
         * @since 2.0.0
         * @example
         * Math.clamp($stat, 0, 200) // Clamps $stat to the bounds 0–200 and returns the new value
         * Math.clamp($stat, 1, 6.6) // Clamps $stat to the bounds 1–6.6 and returns the new value
         */
        clamp(num: number | string, min: number, max: number): number;

        /**
         * Returns the whole(integer) part of the given number by removing its fractional part, if any. Does not modify the
         * original.
         * @param num The number to truncate to an integer.
         * @since 2.0.0
         * @example
         * Math.trunc(12.7) // Returns 12
         * Math.trunc(-12.7) // Returns -12
         */
        trunc(num: number): number;
    }
}

export {};