curl --request GET \
  --url https://{defaultHost}/stats/schema

{
  "reporting_categories": [
    {
      "name": "<string>",
      "line_categories": [
        "<string>"
      ]
    }
  ],
  "groupings": [
    {
      "name": "<string>",
      "line_categories": [
        "<string>"
      ]
    }
  ],
  "line_categories": [
    {
      "key": "<string>",
      "description": "<string>",
      "grouping": "<string>",
      "reporting_categories": [
        "<string>"
      ]
    }
  ]
}