Configuring keyboard shortcuts

a-z
0-9
A-Z

any standalone letter (without 'alt+', 'ctrl+', 'shift+' prefixes)

shift+[left or up or down or right arrow or delete or space]

shift+<key> is ONLY supported for left or up or down or right or delete or space. Use the resulting character for the other characters in combination with shift. e.g. shift+a is A

Otherwise use the shift+<keycode> notation at the next line.

We introduced the shift+<X> notation for being able to use the shift by relying on keycodes for internationalization.

e.g. shift+3 becomes "§" on a German keyboard but "#" on an US keyboard
We cannot make a shortcut that would be international by using shift+3, so we use instead shift+<51>.
Find out the keycode of your key at http://keycode.info/.

 supported only if not used by the browser

 ctrl+shift+[key] is ONLY supported for left or up or down or right or delete or space. Use the resulting character for the other characters in combination with shift. e.g. shift+a is A
Otherwise use ctrl+shift+<keycode> at the next line.

We introduced the ctrl+shift+<X> notation for being able to use the shift by relying on keycodes for internationalization.

e.g. ctrl+shift+3 becomes ctrl+"§" on a german keyboard but ctrl+"#" on an US keyboard
We cannot make a shortcut that would be international by using ctrl+shift+3, so we use instead ctrl+shift+<51>.
Find out the keycode of your key at http://keycode.info/.

cannot be overwritten from the code! You need some browser plugin to overwrite it in your browser.
https://askubuntu.com/questions/162700/how-can-one-disable-shortcuts-of-chrome