What kind of string has to be in the scope function

[EvilWatermelon]

I'm a bit confused about the bearer example of HttpAuthentication.

async fn validator(
    req: ServiceRequest,
    credentials: BearerAuth
) -> Result<ServiceRequest, (Error, ServiceRequest)> {
    if credentials.token() == "mF_9.B5f-4.1JqM" {
        Ok(req)
    } else {
        let config = req.app_data::<bearer::Config>()
            .cloned()
            .unwrap_or_default()
            .scope("urn:example:channel=HBO&urn:example:rating=G,PG-13");

        Err((AuthenticationError::from(config).into(), req))
    }
}

let middleware = HttpAuthentication::bearer(validator);

What does the String literal means in scope("urn:example:channel=HBO&urn:example:rating=G,PG-13") and what do I need to use to validate my token?