Collections Endpoint Documentation Base:

Get a list of Collections by passing a GET request.

A collection is just a specific aggregation.
This endpoint is just a convenience-endpoint
to get aggregations where the aggregationtype=collection.

Get the data for a specific collection at the /aggregations endpoint:
'/collections?coll={collection}'.

GET /collections?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "message": "malformed request"
}