Resolved Unity inspector similar to the screenshot provided

The unity inspector of the Cinemachine TargetGroup has an inspector that has this:


It looks like a List that holds variables

How can I achieve this in my own game?

 

It's just a collection of a serializable class/struct with a custom inspector/property drawer.

https://docs.unity3d.com/ScriptReference/Editor.html
https://docs.unity3d.com/ScriptReference/PropertyDrawer.html

They're deep subjects so lots of learning ahead of you.

 

Thanks. I will definitely check that out.