If you run a public unauthenticated relay you act as a home relay for whoever has your relay configured in their relay map and is close in terms of latency.

So you might get a lot of traffic. You can configure rate limiting, as we do on our public relays.

The traffic is fully encrypted and can not be decrypted by the relay. The only information the relay has is what is necessary for it to function - the endpoint id and ip addresses of the endpoints that are connected to it at any given time, as well as endpoint pairings.

You relay encrypted traffic with no egress to the open internet. So if you want to compare it with Tor, it would be like a tor guard/middle relay, not an exit node.