That quote is from the Atari HQ article.The Duo FC and Duo FC Plus are 8088- and 80286-based machines, respectively, that also contain a Nintendo engine. So you can go from Lotus 1-2-3 to Super Mario Brothers at the flip of a switch.
It's unclear what sort of relationship Duo had with Nintendo or whether this product actually shipped. Since Duo says they get their hardware from Nintendo, can we assume this isn't a clone system? Anyone seen this thing before?