Problem Description

Steps to Reproduce

Create a new MongoDB instance 5.0rc and connect to it.

Create database and collection

Add a single document {"a":1}

Click "Indexes" tab

Click "Create Index" button.

See field names of 0, 1, 2, 3, a in the "Select a field name" dropdown.

Select "3".

An index named "3" is created but it's unclear what field this refers to. And, what keys are named 0, 1, 2, 3 ?

Expected Results

Expected only to see the newly-created "a" field name for creating an index on.
Did not see any Compass documentation that explains this behavior, https://docs.mongodb.com/compass/current/indexes/

Actual Results

Additional Notes