It’s actually the opposite. The corner radii are defined by the window type and the concentricity of its elements.

People who lack attention to detail just think things are randomly different.

I think I know what you (and Apple) mean, but it doesn't make sense IMHO.

Because then, in apps without a toolbar, like Terminal, the window corner is concentric with the close button and has a smaller radius.

In apps with a toolbar, it still concentric with the close button, but has a larger radius. Because it probably also tries to be concentric with and accommodate toolbar items on the right-hand side.

But then, why not just keep the larger radius for both window types, so they are consistent? It wouldn't break concentricity and you wouldn't have non-matching corners, especially a the bottom, where there's usually few or no elements to be concentric with anyway.

That's exactly the kind of detail I'm talking about. There is a nice idea behind it, but it has not been thought through IMHO.