/usr/share/X11/xkb/symbols/ Current File: //usr/share/X11/xkb/symbols/terminate

default  partial modifier_keys
xkb_symbols "ctrl_alt_bksp" {
    key <BKSP> {
        type="CTRL+ALT",
        symbols[Group1] = [ NoSymbol, NoSymbol, NoSymbol, NoSymbol, Terminate_Server ]
    };
};