Rule 5.60 Failure of Respondent to File Brief

Here's a plain English summary of this rule:

If you're the respondent (the person defending against an appeal) and you don't file a brief, you give up your chance to argue your side. The court will only look at the appellant's opening brief and hear the appellant's oral argument when deciding the case.

This means you lose your voice in the process. The judges won't hear your side of the story in court, and they'll make their decision based only on what the other side has presented. If you want any say in how the appeal turns out, you need to file your brief on time.