docs: @SneakyThrows
      protected String getBackupMetadataFilenamePrefix(final AbstractResource metadataResource, final SamlRegisteredService service) {
          val mdFileName = metadataResource.getFilename();
          if (StringUtils.isBlank(mdFileName)) {
              throw new FileNotFoundException("Unable to determine filename for " + metadataResource);
          }
          val fileName = service.getMetadataLocation();
          val sha = DigestUtils.sha(fileName);
          LOGGER.trace("Metadata backup file for metadata location [{}] is linked to [{}]", fileName, sha);
          return sha;
      }