How do I remove CODE: var Client = new SWFObject ("domain.de/game/gordon/PRODUCTION-201602082203-712976078/habbo.swf", "client", "100%", "100%", "10.0.0");
So it works anyway.
Well, no matter what you can still steal it. Just F12 and check network when going onto the client.
You wont be able to "hide" it, but you can do like habbocity does, when opening the client.php - it loads another php sript, where all the vars is defined.
You could always just encrypt your Habbo.swf to only work for your domain name, people can always decrypt it, but I doubt your swf is that good that people will go through the trouble to decrypt it.