curl --request GET \
  --url https://api.kit.com/v4/broadcasts/{id} \
  --header 'X-Kit-Api-Key: <api-key>'

{
  "broadcast": {
    "id": 40,
    "publication_id": 31,
    "created_at": "2023-02-17T11:43:55Z",
    "subject": "You'll never guess...",
    "preview_text": null,
    "description": null,
    "content": null,
    "public": false,
    "published_at": null,
    "send_at": null,
    "thumbnail_alt": null,
    "thumbnail_url": null,
    "public_url": null,
    "email_address": "greetings@kit.dev",
    "email_template": {
      "id": 6,
      "name": "Text Only"
    },
    "subscriber_filter": [
      {
        "all": [
          {
            "type": "all_subscribers"
          }
        ]
      }
    ]
  }
}