So, you know how grown-ups need to prove their age sometimes, like when they go to buy something that's only for grown-ups or when they want to go see a movie that's only for older people? That's called proof of age.
Now, imagine there are some people who want to make sure that everyone is following the rules about age. They might do something called a proof of age inquisition, which means they ask people to prove how old they are to make sure they are following the rules.
It's kind of like when you have to show your parents your report card to prove you are doing well in school. They just want to make sure everything is okay and everyone is safe.
So, a proof of age inquisition is just a way to make sure everyone is following the rules about age and being safe. It might seem a little intense, but it's just meant to keep everyone honest and safe.