A more thorough explanation:

Pretrial is a legal hearing that takes place before a trial. It is also known as a pretrial conference or pretrial review. During this hearing, all parties involved in the trial try to determine the issues, laws, or facts that matter before the court trial.

In civil cases, pretrial discovery occurs when the attorneys of both parties agree on relevant facts or evidence and put them into an agreement. This consensus will be binding for the subsequent procedure of the trial. For example, in a personal injury case, the plaintiff's attorney may present medical records and bills to the defendant's attorney to prove the extent of the plaintiff's injuries and the cost of their medical treatment.

In criminal cases, the court may hold one or more pretrial conferences. During these conferences, the defense and prosecution exchange information about the case and discuss what evidence will be presented in court. For example, the prosecution may present a video recording of the defendant committing the crime, and the defense may argue that the video is not admissible because it was obtained illegally.

It is important to note that any crime or evidence beyond the memorandum agreed by the defendant or their lawyer will not be used against them according to the Federal Rules of Criminal Procedure Rule 17.1. This means that if the defense and prosecution agree to only use certain evidence during the trial, no other evidence can be presented.