Material Class - Creating new Sub Tabs for Different kinds of Characteristics

I have a question regarding classification view in Material Master :

There is a custom Class "Z8C_MATERIAL_CLASS" of class type "001" material class.

I know that when you usually add characteristics in material class they are listed as a single list in "General" tab in classification view of material master.

But, for this class "Z8C_MATERIAL_CLASS" there are sub-tabs listed in material classification view with characteristics :

Example :

Tab 1 : "GENERAL", Tab2 : " LABELLING", Tab5 : "Tech SVCS"

The characteristics are listed in different tabs as needed.

Can someone help me with how are the sub tabs "LABELLING" created ?

When I copied the class "Z8C_MATERIAL_CLASS" to a test material class and used it the tabs did not appear.

Thanks a lot for your help. I have attached the screenshot below :