There was a question on Twitter that I'd thought I'd answer here, for ease of anyone trying to understand. It was from Lily Ray and asked:
"Is it possible to get clarification about how the different ranking systems play into the core update system (or not)"
As the page explains, it covers:
"some systems that are part of our core ranking systems, which are the underlying technologies that produce search results in response to queries"
So in terms of the "core update system," it's not that we have such a thing. We have core ranking systems, multiple systems, which get help us produce results generally. Occasionally, we update these ranking systems. When we do, we share about that as a
core update -- the
core systems are updated. Our blog post today talks about also why we're going to be talking about "systems" apart from "updates" to help better clarify such things.