The confusing thing is that the maker page Mike pointed to continues the fantasy that A6 and A7 are Analog or Digital in some places, while at the same time in one location at least both says they're analog only, at the same time listing them as Analog and Digital.
Can we really blame newbies for being confused, when two years after publication by such an organization, 15 years after the 'Nano debuted, no correction has been made? I had to ask the "Arduino Team" to correct the diagram that was on their website, back in '21, and to their credit they did so.