If you look at the values.yaml of the IKO's Helm chart you'll find:
useIrisFsGroup: false
Let's break down what it is and in what situations you may want to set it to true.
FsGroup refers to the file system group.
Security in IT is the protection of computer systems from the theft and damage to their hardware, software or information, as well as from disruption or misdirection of the services they provide.