Thanks for the reply @joshua.

Although I still don't know if it is possible to set POST Header fields, the Kickstart file allows to do this by defining the tenantId in the root of the request. I'll paste it here directly, to make it easier for other visitors

    {
      "method": "POST",
      "url": "/api/application",
      "tenantId": "#{secondTenantId}",
      "body": {
        "application": {
          "name": "My Cool Application"
        }
      }
    }

Thanks for the reply @joshua.

Although I still don't know if it is possible to set POST Header fields, the Kickstart file allows to do this by defining the tenantId in the root of the request. I'll paste it here directly, to make it easier for other visitors

    {
      "method": "POST",
      "url": "/api/application",
      "tenantId": "#{secondTenantId}",
      "body": {
        "application": {
          "name": "My Cool Application"
        }
      }
    }

I am writing a kickstart file, and I need to define the X-FusionAuth-TenantId header for the /api/application endpoint.
However, I can find no documentation on how to do this in Kickstart, nor how I can get around this.

Is this supported by Kickstart?