A Tor exit relay is the final relay in a Tor circuit. It forwards traffic from the Tor network to its destination on the public internet, so the destination generally sees the relay’s IP address rather than the original user’s.
Because an exit relay handles traffic leaving Tor, an untrusted or compromised relay can observe or interfere with unencrypted connections. It cannot normally decrypt properly authenticated, encrypted protocols such as SSH, but it may redirect a connection or present a different server. SSH host-key verification helps detect this: an unexpected key should be treated as a warning, not accepted casually. Tor provides a degree of origin privacy; it does not verify that the destination or connection path is trustworthy.