A more thorough explanation:

Reddidit se is a Latin term that means "he has rendered himself." In history, it referred to a person who appeared in court to discharge bail.

For example, if someone was arrested and released on bail, they would have to appear in court on a specific date. If they failed to appear, the court would issue a warrant for their arrest. However, if the person showed up in court on their own, they would be considered a reddidit se.

Another example would be if someone was acting as a surety for another person's bail. If the person failed to appear in court, the surety could either pay the bail or bring the person to court themselves. If the surety chose to bring the person to court, they would be considered a reddidit se.