curl --request GET \
  --url https://api.maesn.dev/accounting/journalEntries/{journalEntryId}/Attachments/{attachmentId} \
  --header 'X-ACCOUNT-KEY: <x-account-key>' \
  --header 'X-API-KEY: <x-api-key>'

{
  "meta": {
    "warnings": [
      "Field not used by target system"
    ],
    "pagination": {
      "total": 123,
      "perPage": 123,
      "currentPage": 123,
      "totalPages": 123
    }
  },
  "data": "file content"
}