code: function removeBinding(key, platform) {
          if (!key || ((platform !== null) && (platform !== undefined) && (platform !== brackets.platform))) {
              return;
          }
  
          var normalizedKey = normalizeKeyDescriptorString(key);
  
          if (!normalizedKey) {
              console.log("Failed to normalize " + key);
          } else if (_isKeyAssigned(normalizedKey)) {
              var binding = _keyMap[normalizedKey],
                  command = CommandManager.get(binding.commandID),
                  bindings = _commandMap[binding.commandID];
  
              // delete key binding record
              delete _keyMap[normalizedKey];
  
              if (bindings) {
                  // delete mapping from command to key binding
                  _commandMap[binding.commandID] = bindings.filter(function (b) {
                      return (b.key !== normalizedKey);
                  });
  
                  if (command) {
                      command.trigger("keyBindingRemoved", {key: normalizedKey, displayKey: binding.displayKey});
                  }
              }
          }
      }
docs: Remove a key binding from _keymap
  
  @param {!string} key - a key-description string that may or may not be normalized.
  @param {?string} platform - OS from which to remove the binding (all platforms if unspecified)