Steps to Reproduce
Navigate to Service Catalog > Catalog Definitions > Maintain Items.
Select an item.
Under Related Links, go to Variables and click New.
Add a variable with the following values:
Type: Container Start
Select Display Title
Add another variable to contain and a Container End variable to the item.
Click Try it to test the variable on the UI.
Find the item in the Service Portal.
Note that the expand and collapse widget is not available on the Service Portal.
There are no plans to support this functionality in the baseline functionality of the Service Portal. Build a custom widget to implement this behavior.
Related Problem: PRB706677