The site said that these buttons contain the word "buy" in the filenames, but they were only revealed in jailbroken iPads - devices that have been hacked to take full control of the OS.
The iPad music app currently has no radio functionality, but Apple has long been rumored to be preparing to use its clout with the record labels to launch a music streaming or radio service on devices.
In September last year, The New York Times reported that Apple was in talks with labels about launching a service that would compete with the likes of Spotify and Pandora. The paper reported that the streaming service would be tailored to a user's tastes, most probably with custom and suggested playlists.
A month later, Bloomberg also reported music streaming label talks, and said that they had accelerated. It said that the service could launch in the first quarter (January to March) 2013. However, a separate report claimed that the negotiations were being hindered by a dispute between Apple and Sony.
The discovery of Apple's "radio button" files follows the release of an untethered jailbreak for iOS 6.1 by a group of hackers known as the evad3rs.
Their evasi0n tool is now available for Mac, Windows and Linux, and gives users complete control of their device's operating system. This means they can instal custom themes and download apps not sanctioned by Apple's App Store.
The evasi0n jailbreak is the first to support Apple's latest devices - the iPhone 5, iPad mini and fourth-generation iPad - but it also supports older devices that can upgrade to iOS 6.1, such as the iPhone 4, 4S and 3GS.