The subcomponents of the Popover component are not exposing their TypeScript types, for example as we can witness here:

This is due to how the component is put together and exported:

As we can see demonstrated in the Menu component, there are ways to expose the types correctly with dot-notation subcomponents. When done correctly, the subcomponents can also be documented in the Storybook props tables, as we can see in the one for Menu.

There is also some more information in the Naming Conventions section of the Contributing Guide.