The page you linked to describes a slightly different feature, namely the ability to restrict and override the resource requirements of Pods at the time they are submitted to the system. So it's part of the admission control system, not part of the scheduling.
Thanks davidooo - I was specifically referring to the section on "limits at the point of creation" which gives a practical example of using limits in a multi-namespace (multi-tenant) environment. (https://github.com/GoogleCloudPlatform/kubernetes/blob/maste...).
The new documentation you linked to has good explanations in it as well.
The documentation on resource-based scheduling is at https://github.com/GoogleCloudPlatform/kubernetes/blob/maste...