croll lock. This is always the most recently locking element.
       */
      get currentLockingElement() {
        return this._lockingElements[this._lockingElements.length - 1];
      },


      /**
       * Returns true if the provided element is "scroll locked," which is to
       * say that it cannot be scrolled via pointer or keyboard interactions.
       *
       * @param {HTMLElement} element An HTML element instance which may or may
       * not be scroll locked.
       */
      elementIsScrollLock