Nintendo says Famicom cartridge holes were just a part of the design
The NES and Famicom are very different. Even from a design perspective, the two are dissimilar in many ways.
One interesting aspect about the Famicom is that the cartridges have two holes at the top. On the NES, these don’t exist at all. NES cartridges have indentations at the top, which we know are used to snap the cart in place.
As for the Famicom, the mystery behind those holes have been a mystery. Afternoon News asked Nintendo about them in hopes of seeking clarification. And as it turns out, they were apparently there simply because they were a part of the design.
Kotaku translated the exchange as follows:
Afternoon News: ‘I believe there are holes on the top of [Famicom] cartridges. Do you know what kind of meaning they had?’
Nintendo: ‘Yes, to be honest, they were just part of the design.’
Afternoon News: ‘Um, these aren’t holes made during the molding or the assembly?’
Nintendo: ‘That’s correct. They’re just [part of the cartridge’s] design.’
Afternoon News: ‘Then, the holes on the front and the back of Irem’s cartridges are also design?’
Nintendo: ‘That’s correct. Similarly, that’s the design.’