public List<UniqueId> getContainedReceiptIds() {
            return zipItems.stream()
                    .filter(zipItem ->
                            zipItem.type().equals(StroomZipFileType.META))
                    .map(ZipItem::getContentAsAttributeMap)
                    .map(attributeMap ->
                            attributeMap.get(StandardHeaderArguments.RECEIPT_ID))
                    .map(UniqueId::parse)
                    .toList();
        }
The {@link UniqueId} of the wrapping zip
stroom-proxy/stroom-proxy-app/src/test/java/stroom/proxy/app/MockFileDestination.java