[Findecanor]

A similar bit-flipping trick was used to swap between numeric row + symbol keys on the keyboard, and the shifted symbols on the same keys. These bit-flips made it easier to construct the circuits for keyboards that output ASCII.

I believe the layout of the shifted symbols on the numeric row were based on an early IBM Selectric typewriter for the US market. Then IBM went and changed it, and the latter is the origin of the ANSI keyboard layout we have now.