Not sure about the AUR, but the site goes down all the time and the creator has been MIA for months in the past. It’s still on flathub and you can download publicly maintained keydbs, so even if the creator and website vanished permanently it’ll keep working. If it were to stop working at some point you could probably cobble together a replacement with a few other tools: aaru to dump the disc, something to decrypt the aacs files, and mkvtoolnix to remux.