jordan The resolution would have been whatever the eink res is.
If this is their current model, the specifications show a native resolution of 2200x1650 (4:3). At 13.3 inches, the macOS UI would be incredibly small at standard resolution. Your photo looks like it could plausibly be 2x retina (1100x825), but to me it looks slightly smaller than that, like a possible fractional scale setting. It sounds as if you no longer own the machine, so of course I understand but I was curious about fractional scaling being a factor. I am assuming there was no visible flicker after StillColor was enabled, at least?
DisplaysShouldNotBeTVs Because of this, e-ink devices usually show a lot of flicker while scrolling or during animations. This often creates artifacts in areas that aren't moving too, even if the PC's signal has no dithering
I believe he said the same e-ink screen was comfortable on a Windows laptop, so I assumed he kept all other factors equal between the two when comparing, but only he could clarify that.