curl --request GET \
  --url https://api.tilt.io/api/v1/custom/benchmark_indexes/{benchmark_identifier}/ \
  --header 'Authorization: Bearer <token>'

{
  "name": "<string>",
  "identifier": "<string>",
  "ticker": "<string>",
  "direct_indexing_supported": true,
  "expense_ratio": "<string>",
  "constituents": [
    {
      "tilt_asset_id": "<string>",
      "weight": "<string>"
    }
  ],
  "constituent_count": 123
}