curl --request GET \
  --url https://api.jtl-cloud.com/erp/v2/salesOrders/customfields \
  --header 'Authorization: Bearer <token>' \
  --header 'x-tenant-id: <x-tenant-id>'

[
  {
    "attribut": {
      "id": 123,
      "istMehrsprachig": 123,
      "istFreifeld": 123,
      "sortierung": 123,
      "beschreibung": "<string>",
      "bezugstyp": 123,
      "ausgabeweg": 123,
      "istStandard": 123,
      "feldTypId": 123,
      "regEx": "<string>",
      "gruppeName": "<string>",
      "readOnly": 123,
      "aktivFuerArtikelOhneWarengruppe": true,
      "istPflichtfeld": true,
      "attributId": "<string>",
      "istUnsichtbar": true,
      "skipHooks": true,
      "feldTyp": {
        "id": 123,
        "name": "<string>",
        "datenTyp": 123,
        "regEx": "<string>",
        "skipHooks": true
      },
      "bezeichnungen": [
        {
          "attributId": 123,
          "spracheId": 123,
          "name": "<string>",
          "wertListe": "<string>",
          "skipHooks": true
        }
      ]
    },
    "customFieldId": "b45f6432-2462-4c6f-b00f-1d9d01000000",
    "groupName": "<string>",
    "name": "<string>",
    "possibleValues": [
      "<string>"
    ]
  }
]