What goes in RequestBody content field?

The OAS indicates that a Request Body contains the content field which should be of type Media Type but it seems that the top level object within the content field is really content-type and then that contains the schema. Why is there a disconnect here? Am I misunderstanding the documentation? Shouldn't Request Body's content field be content-type rather than media type?

the documentation I refer to is here https://swagger.io/specification/#request-body-object