Yes, we also had lessons about the differences between BE and AE so we are aware of both, it is just that when Brian was in the kitchen, he was asking about the colour of something.

The reference to Brian being in the kitchen is understandable only for Gen X in France. (https://fr.wikipedia.org/wiki/Where_is_Brian%3F, only in French unfortunately but you also have https://youtu.be/11jG7lkwDwU?si=gQoVL_AmBfQMrZbX&t=57)

Not "only" come on, I'm a little bit younger and I know it too ahah You even linked a youtube video, which I assume is the sketch in question (at work, no youtube): we can look at things from the past and learn them too !

Actually I posted my comment about who can understand it before adding the Wikipedia link, where I learned that Gad Elmaleh did a sketch about that (where a lot of people post GenX presumably learned about the expression).