Most people don't know "what" anything is in that case. Cars? Most people don't know what a clutch master cylinder is - they just know how to use the car. Most people don't know what an app is, since they don't understand the code language it was built in. Sure, they know how to use it but without knowing Java, it may as well be magic. Vaccines! No one knows what they are! There's no simple explanation so everyone who's ever used a vaccine has no idea what they are!

The average person does not have specialized knowledge about anything, even things ubiquitous to modern life.

Yeah, Trump is technically right here but at the end of the day, I don't really care if a firefighter knows exactly how every app on their phone works, just as long as they know how to put out fires and maybe rescue cats from trees.