> A prefilled list is never an acceptable solution for a search box.
Yes it is. When the query is more expensive than the entire dataset included in some other query, a static list built from previously queried content is the more performant search, even if you want to classify it as a filter. I, as a user, am still searching through this list of unknown nodes even if you, the program, are just filtering what your nodes are for me. All searches are filters; hard lines for best practices only matter insofar as they engage with their practical application.
I can't quite follow your comment.
If you have a predetermined number of things that can be "searched" for, that is a filter box, not a search box. Even if you want to stretch the semantics and call it a search box, it is still a solution that only works for a very small subset of the search box problem space. Your criticism that this semanically stret hed snall subset wasn't explicitly excluded is just silly.