[grun]

Hey! I'm Ansgar. I build Arc. The impact is negligible. Notably, Arc never uses cellular connections -- both to preserve battery life and never use cellular data. Wi-Fi (or ethernet) only. And all activity ceases as soon as the tab with Arc is closed.

[gnabgib]

WebRTC doesn't expose whether it's a cellular connection?

[dest]

You can get this info with public IP vs common databases like Maxmind