curl --request GET \
  --url https://api.elections.kalshi.com/trade-api/v2/milestones/{milestone_id}

{
  "milestone": {
    "id": "<string>",
    "category": "<string>",
    "type": "<string>",
    "start_date": "2023-11-07T05:31:56Z",
    "end_date": "2023-11-07T05:31:56Z",
    "related_event_tickers": [
      "<string>"
    ],
    "title": "<string>",
    "notification_message": "<string>",
    "source_id": "<string>",
    "details": {},
    "primary_event_tickers": [
      "<string>"
    ],
    "last_updated_ts": "2023-11-07T05:31:56Z"
  }
}