Why was there an M on his shirt…?

This is as it is Mauvais decision dinosaur (who appears at some other point- can’t remember when) bad decision dinosaur’s French cousin

Mauvais Dinosaur de Décision

I think he’s possibly Canadian…?

Sorry, he’s actually Spanish – Mala Decisión Dinosaurio. But there is a French/Canadian Dinosaur around somewhere as well!

WHOO FRENCH BAD DECISION DINOSAUR

The French Bad Decision Dinosaur was responsible for the Maginot Line

https://www.britannica.com/topic/Maginot-Line