the cluster currently i'm working on has multiple name spaces with a kube-system namespace.

there is 1 nginx-ingress-controller ( which uses nodeport service ) in kube-system namespace and every other name space have their own ingress controller files which are saved as '.ingress' in repository. i see that the rules for each namespace are applied to coming requests, however i'm not able to see any relation between kube-system ingress controllers and namespace controllers

what i'd like to understand is ;

• what is the relation between kube-system namespace and other namespaces for the configs which start with "."

  is there any practical use case like kube-system namespace uses .ingress , .pv , .svc in other name spaces ?