docs: @SuppressFBWarnings(value = "DMI_COLLECTION_OF_URLS", justification = "Only local URLs involved")
      private Map<ConfigurationKey, Object> readFileProperties(Set<URL> files) {
          Map<ConfigurationKey, Object> found = new EnumMap<ConfigurationKey, Object>(ConfigurationKey.class);
          for (URL file : files) {
              ConfigurationLogger.LOG.readingPropertiesFile(file);
              Properties fileProperties = loadProperties(file);
              for (String name : fileProperties.stringPropertyNames()) {
                  processKeyValue(found, name, fileProperties.getProperty(name));
              }
          }
          return found;
      }