I think they mean the used assets would be in a folder (e.g. 'assets') where if you 'install' the game that folder is accessable (like with old games such as doom where the files are changeable or take-able/modifiable or such as elder Scrolls oblivion where we can take the art/sounds etc..... If we wanted).
I could be wrong.. but that's the overall impression I got.
Maybe they could encrypt the used assets or something to make accessing them not worth the time or effort & include a copywrite notice.