A more thorough explanation:

De warrantia diei is a legal term that comes from Law Latin. It means "of warranty of day." In history, it was a writ that ordered a judge not to punish a party for not showing up in court because the Crown guaranteed that the party was busy serving the Crown.

For example, if a person was summoned to appear in court but failed to show up, the judge could issue a default judgment against them. However, if the Crown had issued a de warrantia diei writ, the judge would not be able to issue a default judgment because the Crown had guaranteed that the person was busy serving the Crown.

Another example could be a soldier who was summoned to appear in court but was unable to do so because they were on active duty. If the Crown had issued a de warrantia diei writ, the soldier would not be punished for not showing up in court because the Crown had guaranteed that they were busy serving the Crown.

The examples illustrate how a de warrantia diei writ could be used to protect a person from being punished for not showing up in court. The writ was issued by the Crown to guarantee that the person was busy serving the Crown and could not appear in court. This was important because the Crown needed its soldiers and other officials to be available to serve the Crown, and it did not want them to be punished for doing so.