Look at how Gary Illyes explained it when Kenichi Suzuki asked in this Google+ thread:
Question: What is "Core Ranking Algorithm" at all? How different is it from algos that aren't a part of it?
Answer from Gary:
A2. I think this is really the worst takeway of the past few days, but imagine an engine of a car. It used to be that there was no starter (https://en.wikipedia.org/wiki/Starter_(engine)), the driver had to go in front of the car, and use some tool to start the engine. Today we have starters in any petrol engine, it's integrated. It became more convenient, but essentially nothing changed.
For a user or even a webmaster it should not matter at all which components live where, it's really irrelevant, and that's why I think people should focus on these "interesting" things less.
So, he said, "essentially nothing changed" it just seems to make it "more convenient" for Google to turn on the engine and maintain?
But what threw me for a loop is that John said that now that Panda is integrated, webmasters should notice it less. I mean, in the past, Panda was noticed a lot. So that would be a change and it would be different. But with Panda 4.2, the last official Panda update, many webmasters did not notice it - so it isn't far off from that.
So has nothing changed? It is a bit confusing as you can see.
Forum discussion at Google+.