// Create clones for remaining windows that should be
        // visible in the Overview
        this._windows = [];
        this._windowOverlays = [];
        for (let i = 0; i < windows.length; i++) {
            if (this._isOverviewWindow(windows[i])) {
                this._addWindowClone(windows[i]);
            }
        }

I think "remaining" here above refers to the way we used to find and special case the desktop window if any - has no relevance to current code.