A recently granted patent from Google is about supporting querying and predictions, and it does this by focusing on user-specific knowledge graphs.
Those User Specific Knowledge Graphs can be specific to particular users.
This means Google can use those graphs to provide results in response to one or more queries submitted by the user, and/or to surface data that might be relevant to the user.
I was reminded of another patent that I recently wrote about when I saw this patent, in the post Answering Questions Using Knowledge Graphs, where Google may perform a search on a question someone asks, and build a knowledge graph from the search results returned, to use to find the answer to their question.
So Google doesn’t just have one knowledge graph but may use many knowledge graphs.