There is no special key on English keyboards for the '^' key, it is just Shift+6.

The '^' German keyboards is used for the Tilde '~' key on English keyboards.

So the answer is: Use InputButton.Tilde, I guess you want to use it to open up a console in game?

For normal text input you don't need to worry about this, all text going through Input.Keyboard.HandleInput will work (you could check if a '^' was entered there, then it won't matter where it is on the keyboard).

This is correct. Keep in mind that the InputButton enum is ONLY useful to detect each keycode. It has not much to do on what your system will show when you press that key (it will be different depending on your keyboard layout, if shift, control, alt, alt gr, etc. are pressed).

InputButton.Tilde will be pressed when you press the key below the Esc key, it does not matter which keyboard layout you use. As long as the keycode for Tilde (192 in this case) is returned from the keyboard, the InputButton will go into the Pressed state.

If you press InputButton.RightAlt (Alt Gr in Germany) and InputButton.Plus, then exactly those keys will go into the Pressed state. They will not set any other keys like InputButton.Tilde into the Pressed state because it was not pressed.

So maybe just write a helper method calling Input.Keyboard.HandleInput to check which key characters were pressed. Or write some custom code where you check for the keyboard settings and handle it differently (not recommended, almost no game does this anyway, instead you usually have slightly different input settings for different languages or games make no difference at all and users have to reconfigure if their keys are at different locations).