I think the key thing is that Spotlight is now creating a... knowledge graph? of everything on your device for Siri's consideration. That's potentially very useful.
they specifically said "Splotlight Semantic Indexing" which means they generate embeddings of all your "personal context" and store it in a local vector database so they can do on-device RAG.
I suspect it is Kuzu in the backend. I had called it out earlier this year in my article. ".. WWDC 2026 or 2027 introduces any “contextual intelligence” features in Siri that require cross-app relationship reasoning."https://medium.com/data-science-collective/i-analyzed-163k-l...