Why does the patent ipc of the State Intellectual Property Office display None?

The first type is that the invention application has not been published yet, so it has not been published yet. The second type is utility patent and appearance patent. During the review process, the certificate has not been obtained, so it will not be published on the external website. The third type is utility patent and appearance patent. The first is that after the application is accepted, the application fee is not paid, so this is just a patent application.