What does private[routes] mean?

Question

I have the following code snippet:

final class UserRoutes[F[_]: Defer: JsonDecoder: MonadThrow](
    auth: Auth[F]
) extends Http4sDsl[F] {

  private[routes] val prefixPath = "/auth"
  private val httpRoutes: HttpRoutes[F] =
    HttpRoutes.of[F] {
      case req @ POST -> Root / "users" =>
        req
          .decodeR[CreateUser] { user =>
            auth
              .newUser(
                user.username.toDomain,
                user.password.toDomain
              )
              .flatMap(Created(_))
              .recoverWith {
                case UserNameInUse(u) =>
                  Conflict(u.value)
              }
          }
    }
  val routes: HttpRoutes[F] = Router(
    prefixPath -> httpRoutes
  )
}

that I do not understand the meaning of the expression private[routes] val prefixPath = "/auth". Could anyone please clarify the meaning of the expression?

Answer 1

It means that the prefixPath member is only accessible on UserRoutes from the routes package.