flatten deeply nested JSON with Crawler

They are seeing Arrays and Structs based on the schema of the JSON document.

{
   "event_params":[ {"key":"Value"}, {"Key","value"}],
   "geolocation": { "lat": 56.333333, "lng": 57.44333 }
}

If this is my JSON document, when I run the crawler it will result in this schema

event_params: Array
geolocation: Struct

The customer can use Custom Classifiers in Glue to extract the data further. Or, they can keep it as is, and run a glue job to format the data into a new table in columnar format.