A real-world example of this is a game that wants to use the "W", "A", "S" and "D" keys to control player movement.
Editorial: You could make the point more clearly by continuing the sentence to say "... when a user is using a Serbian keyboard (which has no WASD on the key caps and doesn’t produce w, a, s or d when keys are pressed)." (or something like)
5.2.1. Motivation for the code Attribute https://w3c.github.io/uievents/#code-motivation
Editorial: You could make the point more clearly by continuing the sentence to say "... when a user is using a Serbian keyboard (which has no WASD on the key caps and doesn’t produce w, a, s or d when keys are pressed)." (or something like)