A more thorough explanation:

In a legal case called a qui tam action, the person who helps the government is called a relator. This person is usually a private citizen who has information about someone who is cheating the government. If the case is successful, the relator gets a share of the money that the government recovers.

For example, let's say that an employee of a company that does business with the government finds out that the company is overcharging for its services. The employee could file a qui tam lawsuit against the company. In this case, the employee would be the relator, the company would be the defendant, and the government would be the plaintiff.

Another example of a relator is someone who knows that a doctor is billing the government for medical services that were never provided. This person could file a qui tam lawsuit against the doctor.

The relator plays an important role in qui tam cases because they have inside information that the government may not have. By coming forward and filing a lawsuit, the relator helps the government recover money that was stolen from taxpayers.