> it's still shared

Right, that was really my main question: besides the labeling (which is of course approximate), the positioning sure looks like each core would have its own "favorite" section of the cache. And being shared, it seems like this could make for some interesting performance behaviors.

Ah, interesting, this topology was introduced with Sandy Bridge. I'm just out of date: https://www.anandtech.com/show/3922/intels-sandy-bridge-arch...

Yeah, you need something like that to scale to large core counts, and especially if you wanna pull off some chiplet goodness (like AMD did with Ryzen). I think that's why it got lumped with the Fabric Interconnect layer in one of the block diagrams.