You seem to be referring to a reference counting scheme that is retrofitted into a language, where the application has the responsibility of indicating where, in an application-defined type, the references are to other objects.
That can be true of garbage collection also; it can be bolted on in a way that the application is responsible for providing a handler for traversing objects during marking.
(Of course, it is vastly less likely that a marking traverser would be doing anything other than its job of recursing or otherwise indicating pointers to be traversed, whereas finalization routines will mix the downing of references with other resource clean up.)
That can be true of garbage collection also; it can be bolted on in a way that the application is responsible for providing a handler for traversing objects during marking.
(Of course, it is vastly less likely that a marking traverser would be doing anything other than its job of recursing or otherwise indicating pointers to be traversed, whereas finalization routines will mix the downing of references with other resource clean up.)