That's keyboard code [1] vs. Keyboard key [2].

[1] Physical location of a key https://w3c.github.io/uievents/#keys-codevalues

[2] Mapping of a key https://w3c.github.io/uievents/#keys-keyvalues

The naming is terrible and I have to look it up every single time

What keyboard layout are you using? I can't reproduce on a US layout.

I don't think Backspace as a key was standard internationally until 1994. Apple still doesn't use it, just Delete.

Old terminals had this shenanigans going on too. Backspace was not backspace and so on