curl --request POST \
  --url https://{FUSION HOST}/api/objects/substitutions \
  --header 'Content-Type: application/zip' \
  --data '{}'

{
  "properties": [
    {
      "id": "<string>",
      "schema": {
        "type": "<string>",
        "title": "<string>",
        "description": "<string>",
        "hints": [
          "<string>"
        ]
      }
    }
  ],
  "values": {},
  "zipFileToken": "<string>"
}