The DVD was given out at shops in the UK/ Europe, probably as a pre-order bonus. It contains a making of feature. A 14 pages art booklet is glued to the cardboard sleeve. The back of the sleeve is numbered.
There is a variant with a Game logo on the back, given out at Game in the UK. The discs seem to be identical.
Thanks to eBay member kkukki20022008 (images 1-3).