At first I thought they must be comprising this of all of their Top 10 UK singles, but they've had about 22 of those (including "Absolutely Fabulous"). Plus, "Love etc." charted at #14.
At any rate, the site notes the following:
"The Special Edition version will feature a DVD containing a series of classic BBC TV performances from Top Of The Pops and other shows recorded over the last 25 years as well as Pet Shop Boys' celebrated Glastonbury Saturday night headline show from June which the Daily Telegraph judged to be 'one of the most spectacular Glastonbury moments ever'. The full track-listing will be on this site shortly"
