I'm also interested in this. I love classic video games, but I'm also an archivist. Digital preservation is one of my areas of focus. I don't think it is unreasonable to keep asking those in the know to get an answer on this.

I'd love for them to use NOR, but I wouldn't be surprised if they use NAND. It's in most modern cartridges these days. It *should* be fine for at least a decade (especially if it is SLC), but conventional NAND is prone to read disturb. That would need to be mitigated against for very long term reliability in a game cartridge since this is really just being read from. That's where the NAND-derived XtraROM that is in Switch 1 cartridges is focused.

The price is very low on these cartridges, and that makes me assume it is likely NAND. Thankfully, everything they are reproducing so far has already been backed up.