Remote Video Camera wants STUN connection

Why it isn’t explicitly said as antifeature, that app mentioned wants connection to stun.l.google.com?

If I new, I wouldn’t bother myself testing it, although set up is so simple.

I just wanted to make door video ring bell via LAN only and I definitely don’t need the app, that checks my IP in the web.

That’s not all: the app refuses to work with TrackerControl enabled, even when TC doesn’t detect any trackers.

Do you know any alternative to Remote Video Camera?