curl --request GET \
  --url https://data.kushiro.app/api/v1/sources

{
  "sources": [
    {
      "source_id": "kushiro_population_households_monthly",
      "metric_count": 840,
      "point_count": 0,
      "latest_fetched_at": "2026-04-29T00:00:00.000Z"
    }
  ],
  "count": 1
}