On a Linux OS, you are unable to bind "special keys" as controls, in either the controls menu or a mods control menu. Special keys like backslash and grave are unable to be bound.

You can bind these manually threw editing the options file and use a key code and ingame the key will be bound to that key, but pressing the key won't do anything.

If you try to bind it ingame, it will first not do anything, but if you press it a second time you will bind that key to NONE.

That's the first problem, wher you cannot bind these special keys and you are unable to use them if bound.
The second issue is that if a key is bound to NONE, which technically means no key at all, all special keys that would return NONE will act as the key you just bound.

So if I try to bind a key to grave, so it returns NONE, all the special keys I press will run whatever that key does. NONE does not mean no key is bound on Linux, it means that all keys that would return NONE is bound to that option.