https://tools.ietf.org/html/rfc7946#section-3.3
A GeoJSON object with the type "FeatureCollection" is a FeatureCollection object.
A FeatureCollection object has a member with the name "features".
The value of "features" is a JSON array. Each element of the array is a Feature object as defined above.
It is possible for this array to be empty.
Feature Collection
https://tools.ietf.org/html/rfc7946#section-3.3 A GeoJSON object with the type "FeatureCollection" is a FeatureCollection object. A FeatureCollection object has a member with the name "features". The value of "features" is a JSON array. Each element of the array is a Feature object as defined above. It is possible for this array to be empty.