How must the leaky pipe have been stopped if there is absolutely no hint of the city having been there?

I mean when there is a water main break there is digging involved you see the evidence that digging up happened. That’s fine.
But it is just a stream of water (a small pipe leakage) and a day or so after it was reported it stopped. It’s absolutely dry the day of or the day after the fix. If everything looks exactly the same before and after the leak, (no evidence that any digging went on), how must they have fixed it?