Unless the details they've been given are wrong and it ends up featuring more/new content (it's happened before - The 101ers' Breakdown Avenue Revisited cd didn't come out with a foldout sleeve), it's just the main album (presumably exactly the same remaster as on the '99 and '04 versions), and the documentary/footage from the 25th anniversary package.
Except in cardboard replica LP packaging, (which to be fair, looks nice on the thumbnail pack shot/mockup? but there's already been the the Japanese LP replica release, and the only differences are is that: that was the album on 2cds and this has the dvd, and that - like the singles box - theirs was probably better quality *sticks out tongue in the direction of Sony* ) and a photo, sorry "picture" booklet. This might include some of the unofficial facebook rumoured 'new material' but I'm not holding my breath (more likely familiar photographs that might actually be from the right period and maybe some of the photos and art from the 25th anniversary booklet, if we're lucky)
So no Vanilla Tapes and no sign of the fascinating essay on the background and psychogeography of the band and album, and we don't get the contemporary notes on the songs from Joe, Mick, Topper cartoons from Paul, from their official fanzine The Amagideon Times.
It's a strange world where a Radio 1 documentary & album broadcast has more new content than the official release *hmm* (part of Zane Lowe's Masterpieces this week - new interviews with Mick Jones and Don Letts are promised http://www.bbc.co.uk/radio1/zanelowe/masterpieces/2009/ )
Bet they've forgotten the plastic inner sleeves that the made in Japan cd replicas of other artist's LPs include too, and the discs end up getting scratched on the card, mmm skipping cds & dvds.
eta: Eil's later email plugging this new product they've got in, basically says it's a cut down version of the 25th anniversary edition which is now going to be deleted - but it'll still be available online amazon etc. plus ebay/second hand and shops with older stock. This just makes it even stupider - Sony have taken away a great package that's what historically important deluxe/whatever edition cds should be like and replaced it with something worse.
Eil's info - "London Calling
2009 issue UK '30th Anniversary Edition' 2-disc [CD/DVD] set comprising the original 19-track CD album featuring the classic hits 'London Calling', 'Clampdown', 'Train In Vain' & 'The Guns Of Brixton'; plus a Bonus DVD containing the Don Letts produced documentary 'The Last Testament: The Making Of London Calling' including interviews with Joe Strummer, Mick Jones, Paul Simonon & Topper Headon, music videos and footage of The Clash recording London Calling at Wessex Studios. Presented in a mini-LP style packaging complete with card wallets [holding each disc] and 20-page picture booklet! £ 12.99"