I am currently trying to figure out how to configure a URL Button in a Messenger chatbot, so it opens a link in the window like this:
The thing making me want know the way is that it has this navbar at the top - very neatly looking indeed. I tried setting up a URL button and the result had the target link instead of the navbar.
One hint that I've gotten is that, because the articles that I found these pictures in are dated from 2-3 years ago, Facebook just had removed this interface.
