What Is the Role of a “Whistleblower” or “Reporter” in a Slashing Mechanism?

In many PoS protocols, a "whistleblower" or "reporter" is a node that observes and broadcasts the cryptographic evidence of a validator's malicious act (like double-signing). This reporting node is typically incentivized with a small reward, taken from the slashed stake of the misbehaving validator.

This mechanism decentralizes the monitoring process and encourages constant vigilance against security threats, making attacks harder to conceal.