Various messages are shared between skins and form errors. These concerns should be separated so that skins can be maintained in such a way that they do not need to worry about side effects.
OutputPage::formatPermissionsErrorMessage shares messages that are also used in skins. Offending line is:
$action_desc = $this->msg( "action-$action" )->plain();
This should be updated to use a dedicated message for this context so that skin interface messages can be changed for.
Special:Movepage also uses action-move. This should be updated to use a dedicated message for this context.
To avoid translations, I suggest we copy across existing messages where needed.


