The code found makes references to apps being automatically removed from iTunes after a "rental period", as well as apps being completely deleted from a user's computer. Of course, a rental feature may anger developers who make their money on impulse purchases, but it should make customers far happier with the App Store by not being forced to keep apps they don't want, or apps that aren't what they expected. Amazon offers a "try-before-you-buy" feature through the web portal for its Appstore, and the Android Market has a refund/return policy.
We're hoping that the new feature by Apple may help to get Google to bump its return policy back from 15 minutes to 24 hours, because with a term like "rentals" we can't expect Apple's time limit will be as short as 15 minutes. Don't be surprised if this is part of tomorrow's announcement. Keep it tuned in, and we'll let you know.