The distinction between optical and digital zoom get a little blurred by this kind of camera setup. No pun intended.

Typically cropping and then upscaling.

While I don't think it's right to call these crops "optical zoom", the quality is typically pretty good.

To be fair to the above poster, normally "digital zoom" implies that your standard (un-zoomed) image is at the native sensor resolution, and the zoomed image has reduced resolution because of the crop.

Presumably the standard image on the 16e converts the 48 MP sensor into a 12 MP image with less noise because they bin 4 sensor pixels into 1 pixel in the image file. So a 12 MP crop on the 48 MP sensor would result in a zoomed image with the same 12 MP resolution as the standard image. A major drawback would be higher image noise, but nobody will see a reduction in image pixels. At the end of the day it's probably somewhere between true optical zoom and a 12 MP native sensor with a crop.