private void sortDrawablesNewest() {
        Sort.instance().sort(drawables, (DrawableData o1, DrawableData o2) -> {
            var lastModified1 = (o1.file == null ? 0 : o1.file.lastModified());
            var lastModified2 = (o2.file == null ? 0 : o2.file.lastModified());
            if (lastModified1 < lastModified2) {
                return 1;
            } else if (lastModified1 > lastModified2) {
                return -1;
            } else {
                return 0;
            }
        });
        refreshDrawableDisplay();
    }
Sorts by modified date with newest first.
core/src/com/ray3k/skincomposer/dialog/DialogDrawables.java