Yeah, but for 99% of keyboards the legends were put there by the manufacturer who could also burn into the controller firmware what scheme of legends was used.

Yeah, but for 99% of keyboards the legends were put there by the manufacturer who could also burn into the controller firmware what scheme of legends was used. This way the OS could autodetect whether the keyboard was e.g. QWERTY or AZERTY without having to do a user-involved discovery process like OS X or assuming keyboard matches locality like Windows.