It must be some sort of negative joint system. I've seen some good ones that you can get remade, essentially the are a small metal channel with a flange that lets you screw into them.
A door like this may have been pre-made with metal channel that the panels simply bolt onto.
This is an overhead sectional door. you can tell by the fasteners along the horizontal lines. the vertical line in the centers is most likely cosmetic
It could easily be a sectional overhead door.
It must be some sort of negative joint system. I've seen some good ones that you can get remade, essentially the are a small metal channel with a flange that lets you screw into them.
A door like this may have been pre-made with metal channel that the panels simply bolt onto.