@WilsonTobbe
The OP has received Firefly preinstalled on the ReadyNAS Duo so he has actually paid for something, just not to the Firefly developer.
Netgear provide very little information. The limited information they do provide is hidden so deep that it’s difficult to find.
This is no different to any other NAS vendor that has an “iTunes Streaming Server” on their product
I’ve tried searching Netgears’ knowledge database system for info and get nothing. Yet if you search the ReadyNAS forum you might stumble across a post that contains a link to an article in Netgears’ “KB” system.
The fun part is that Firefly on the ReadyNAS is a svn-1696 / svn-1676 hybrid + a few extra customisations.