public static String getMapRenderScalePreferenceKey(final String themeStyleId, final RenderThemeScaleType scaleType) {
        return themeStyleId + "-" + scaleType;
    }
Shall SOLELY be used by {@link cgeo.geocaching.maps.mapsforge.v6.RenderThemeSettingsFragment}!
main/src/main/java/cgeo/geocaching/settings/Settings.java