@NonNull
    public static String formatMapSubtitle(final Geocache cache) {
        final StringBuilder title = new StringBuilder();
        if (cache.hasDifficulty()) {
            title.append("D ").append(formatDT(cache.getDifficulty())).append(SEPARATOR);
        }
        if (cache.hasTerrain()) {
            title.append("T ").append(formatDT(cache.getTerrain())).append(SEPARATOR);
        }
        title.append(cache.getSize().getShortName()).append(SEPARATOR).append(cache.getShortGeocode());
        return title.toString();
    }
Formatting of the hidden date of a cache

@return {@code null} or hidden date of the cache (or event date of the cache) in human readable format
main/src/main/java/cgeo/geocaching/utils/Formatter.java