Universal Plug and Play (UPnP) often allows your camera to open ports on your router automatically. This is how cameras get indexed. Manually port forward if absolutely necessary, but preferably, do not expose the camera to the internet at all.
But the feed showed otherwise.
The existence of these searchable feeds is a stark reminder of the "Security through Obscurity" fallacy. Many owners assume that because they haven't shared the link to their camera, no one can find it. inurl viewerframe mode motion 2021