[v64]

Not OP, but also have visual aphantasia. Not speaking for others, but for me personally, my mind is entirely auditory. I hear my thoughts as spoken words, and if I'm thinking about something complex, it resembles a crowd of chatter where I can focus in on certain conversations while tuning out the rest.

I majored in math, and when working with equations, I will literally hear in my head things like "eff of ex equals two ex squared plus ex plus five". If I'm multiplying 36 by 7 in my head, I will hear "seven times six is forty-two, hold the two, carry the four, seven times three plus four is twenty-five, the answer is two fifty two."

If that sounds like a difficult way to mentally calculate, I'll note that I'm not a good mental calculator. :) Abstract algebra and logic are much easier for me to grasp than fields requiring more visual intuition like geometry and topology.

Remembering things from a textbook, I usually just remember the content, although there are also cases too where I'll remember I got it from the textbook with the bicycle on the cover or some detail like that, not because I visually remember the bicycle, but rather because I've textually committed that book in my mind as "the book with the bicycle on the cover". If you asked me what color the bicycle is, I won't remember because I didn't note that in my mental description.