He knows there is a phase of the moon called "gibbous" and that it is between half and full.
He can tell us when the next leap year is and on what day of the week his next birthday will be.
But he doesn't know what a McRib sandwich is. They are available year round in Europe - is what we heard on Jeopardy. He's had a few - when they were "in season" here.
He likes them - to my dismay. But right now, he doesn't know or remember what is The McRib.
You'd think if he remembers obscure words that most people forget, that he would remember something important like The McRib.