More like asking an microelectronics engineer how 3 phase motors work. She probably took a course in school although it may have been awhile and it's not her specialty.

It's a feature of engineering and scientific education that there is a corpus of knowledge that every person in a discipline (say EE, or medicine) is expected to have learned (if not retained). I imagine all doctors learn quite a bit about the immune system in medical school.

Given that a "random software engineer on the street" may have a CS degree, an MBA, a 6 week bootcamp, or be totally self-taught, the example isn't analogous IMO.