Quis custodiet ipsos custodes?
“Quis custodiet ipsos custodes?” is a Latin phrase that means “Who watches the watchers?” It asks the question, “Who makes sure that the people in charge are doing the right thing?”
Imagine you have a group of kids making sure everyone follows the rules on the playground. This question is about making sure those kids also follow the rules and behave fairly. It’s important because everyone, even leaders or rule-enforcers, needs to be responsible and do the right thing.
You can read more about it on the Wikipedia page.