code: private static List<String> extractWildcardPrefixes(List<String> propertyKeys) {
  		return propertyKeys.stream()
  			.filter(p -> p.endsWith("*"))
  			.map(s -> s.substring(0, s.length() - 1))
  			.collect(Collectors.toList());
  	}
docs: Converts the prefix of properties with wildcards (e.g., "format.*").