Ok, found it. Likely this line wasn't supposed to be there, because it is only used for setting Cotonti's revision number (which you shouldn't be able to edit through the admin panel).
You can add the language string in system/lang/xx/admin.lang.php on line 35:
$L['core_version'] = &$L['Version'];
I'm guessing this config value will either be removed or modified so it won't show in the config panel.