No, it is nothing like retinal fatigue, which is what they are referencing in that sentence.

The later section on "What Do Most Visualizers See?" is a better description, although the level of detail is highly dependent on effort, and lack of distraction.

And I'd argue that detail is not particularly important as the visualization is just there to represent conceptual things.

The potential value of the after-image test was (hopefully) a concrete way for me to understand better what a visualizer could actually see. From the replies, it seems that it is really a very poor example.

For someone with aphantasia, the failure of the "What Do Most Visualizers See?" section is that it is still just a wall of words. I have to imagine what a visualizer might see, which is, of course, difficult for me!