According to the comment in gnome-keybinding-properties.c:append_keys_to_tree_from_file, keybindings that apply to a window manager that's not the one we're running should not be added into gnome-keybinding-properties dialog.

But according to the following code, if keylist->wm_name is not NULL and if it is contained in wm_keybinding which contains running wm, the keylist will be freed. This is actually opposite to what the comment says. So on systems that run metacity, keybindings for compiz or other wm will be shown in the gnome-keybinding-properties dialog.

  /* If there's no keys to add, or the settings apply to a window manager
   * that's not the one we're running */
  if (keylist->entries->len == 0
      || (keylist->wm_name != NULL && strv_contains (wm_keybindings, keylist->wm_name))
      || keylist->name == NULL)
    {
      g_free (keylist->name);
      g_free (keylist->package);
      g_free (keylist->wm_name);
      g_array_free (keylist->entries, TRUE);
      g_free (keylist);
      return;
    }