code: protected MetaLocale addLikelySubtags(MetaLocale src) {
      // Always return a copy.
      MetaLocale dst = src.copy();
  
      // If the locale has all fields populated (language, script, territory)
      // then do nothing.
      if (src.hasAll()) {
        return dst;
      }
  
      // Build a temporary locale for matching and clear the variant since it
      // is not used for likely subtags.
      MetaLocale temp = src.copy();
      temp.setVariant(null);
  
      // Iterate over the match flags, from most specific to least.
      for (int flags : MATCH_ORDER) {
        set(src, temp, flags);
        MetaLocale match = likelySubtagsMap.get(temp);
        if (match != null) {
          // Use the first match we find. We only replace subtags that
          // are undefined, copying them from the matched locale.
          if (!dst.hasLanguage()) {
            dst.setLanguage(match._language());
          }
          if (!dst.hasScript()) {
            dst.setScript(match._script());
          }
          if (!dst.hasTerritory()) {
            dst.setTerritory(match._territory());
          }
          break;
        }
      }
  
      return dst;
    }
docs: Add likely subtags, producing the max bundle ID.