Probably a bug. Seen in 24.1 (I know I'm a pre-AI dinosour). 

Bug Summary
I have a List, that I use in a Search Configuration.

- In the list of “Lists”, the row says 0 references. 

- when using “Search this app for <listname>”, the search results show the definition of the list, and not the usage in a Search Configuration. 

Use Case
Mostly avoiding errors by developers. Say you find a list that isn't used and delete it. A Search Configuration will then not work. Perhaps the delete will be stopped because a reference exists… but for good order, please show the reference when it exists.

Preferred Solution (Optional)
Well, if it has been addressed in 26.1 then close my suggestion :)
Otherwise, I think all references should be visible when listing “Lists” and when searching app for it.