How does MongoDB sort records when no sort order is specified?

Question

When we run a Mongo find() query without any sort order specified, what does the database internally use to sort the results?

According to the documentation on the m

Answer 1

It is returned in the stored order (order in the file), but it is not guaranteed to be that they are in the inserted order. They are not sorted by the _id field. Sometimes it can be look like it is sorted by the insertion order but it can change in another request. It is not reliable.