This endpoint retrieves the resource for the specified resource Id. Restricted resources cannot be accessed. To access those resources too, you have to use /mydelivery/v1/resources/{fileIdentifier}.
The resource's Id can be obtained using the Authoring assets API: /authoring/v1/assets

{
    "items": [
        {
            "resource": "06763fa56ceec4d5bcafb37b53de2cd1",
            ...

The delivery Url for this endpoint would look like:

/delivery/v1/resources/06763fa56ceec4d5bcafb37b53de2cd1

User roles: admin, manager, editor, viewer, authenticatedVisitor, anonymous