Storage should not be advertised for serverRoot
serverRoot do not contain a pod storage and should not be advertised as such. There should be no header nor link storage
On mono-user https://example.com/ should advertise for Storage. On multi-user pod, only https://user.example.com/ should advertise Storage and not https://example.com/
In practice there should be no bad consequence on always advertising Storage in https://example.com/. On multi-user pod https://example.com is not a solidPod and webId https://example.com/profile/card#me do not exist.
The spec does not prohibit a Storage at example.com/ in addition to user.example.com/ . The constraint is so to not have overlapping URI paths. That's all.