Nginx integration with Fleet - Default dashboards modification

Hello all !
This is a quick (Kibana beginner) question... I am wondering why the response code of the Nginx dashboards are grouped, and is it possible to change that ?

Here is one default panel that came with the Nginx integration with Fleet. I know that I generated 404 response code but it is grouped under "400s" status code, why that ? can I change it or do I need to create a whole new panel ?