The reference is back to a case so…
Say we have Case A and Case B. You can reference Case A in Case B (anywhere in the test Case B) by typing [Case A] where you need it in Case B.
I use it for things like logging into environments and instead of typing it out everywhere I created a Shared Steps suite within a project. In the shared steps I create the basics needed then reference each ‘test’ where needed.
Clicking the Link created by using the [Case B] takes you directly to the Case B steps. Since it is a reference directly to the other case - any change in Case B will change it for any reference.
This is what the link would look like:
This references Case 372 and clicking on the link takes you to case 372.
The link will not work if case 372 is deleted of course.