Previously in Zabbix 5.4 and below when viewing the Services you were able to see a tree of the defined services.

This made it very clear on one page to see what parent and child service relations there were.

After Zabbix 6.0 this was removed and you now how to click through each parent to see which children there are.

This is not really an issue if the services are 'flat' or have a shallow depth.

This becomes a bit of a hide-and-seek game when the service is complex and your trying to see whats what for example:

Service X -> Service X Function -> Service X Components -> Service X Component Primary -> Server Lists etc....