Using an observer design template with push or pull

I am learning the basics of software engineering independently. And there's something I did not understand about the observer design template.

I have this diagram, in this diagram I marked what each part says, whether it is an observer, subject, concreteObserver or adapter.

From this chart I did not understand if it is a model of push or pull. In my opinion it's a pull, but I'm not sure. I think it's Pull, because we inform our Observers that there was a change, and the Observers go and check what the change was and interrogate the subject's state.

I would be happy if you could help me.