This is a simple page showing phone numbers that are substituted based on the incoming link.
Before DNI, it will show a dummy phone number of 1 to 9, then 0. After DNI, it will be a series of ten 1s.
(123) 456-7890
123-456-7890
+1.1234567890
It also works for call links:
If the phone number is not changing, make sure your browser has JavaScript enabled and open this link in an incognito or private window to try again.