A more thorough explanation:

A muster roll is a document that contains a list of all the crew members on a ship. It includes their names, ages, nationalities, and job positions. This document is important for maritime law and is used to determine a ship's neutrality during wartime.

For example, if a ship is stopped by a naval vessel during a war, the naval officers will ask for the ship's muster roll to determine if any of the crew members are from a country that is at war with them. If the ship has crew members from both sides, it may not be allowed to continue on its journey.

Another example is when a ship is inspected by port authorities. They may ask for the muster roll to ensure that the ship is complying with labor laws and that all crew members are accounted for.

Overall, the muster roll is an important document that helps ensure the safety and legality of ships and their crew members.