I wonder if there’s a way of how we can extract other numbers from there.
You could do it with a Python, or even a simple bash script, have it try to do a GET request of the URL in a loop trying every possible phone number combination at the end (or you could restrict it to just a handful of area codes) then if the GET request is successful then its a number they’ve prepped a URL for, if it comes back as page not found/unsuccessful then its not a valid number. Just a thought.