Terms Aggregation Bucket Sort when doc_count is equal

Hey. The documentation states that:

By default, the terms aggregation will return the buckets for the top ten terms ordered by the doc_count

I was just wondering what happens, when the doc_count of several buckets is equal? I observed that buckets are then sorted by their _key/_term but I can't find any information confirming that behaviour.

Greatful, for any information on that. thanks :slight_smile:
Anton