I personally have aphantasia, and, funny enough, I don't visualize anything when I'm coding, or reading code: I just understand the concept more or less deeply, but always without any images: It's just the "concept" that I understand. It's really like if I had an interpreter in my head when reading and when coding, I do the opposite: I know the required sequence and I reverse engineer it to the programming language version.
Do you guys really have schema in mind??