Find hit fields in search result row

Is there any way to find which fields are hit in a search result row?
Is it possible to reliable extract a list of hit fields from FTS search result score explanation? By traversing JSON, or (better) with an SDK strong type.
From highlights maybe.
Fields are indexed to “store”. I can index to "include term vectors "
Motivation: Implementing a custom scoring system by business requirements.

Yes "store"ing and “including the term vectors” are the right things to do while indexing.
Now while running the query, you can request “highlighting” to return fragments of the fields where your search criteria matched.

Here’s a simple example:

  "query": {
    "match": "xyz"
  "highlight": {}

This would default to using a html highlighter.
Here’s some documentation on this - Highlighting | Couchbase Docs