Context: The games are in the form of .ipg files, which are actually .zip archives in disguise[citation needed]. When unzipped, they reveal executable files along with common audio and image files, leading to the possibility of third party games. Apple has not publicly released a software development kit (SDK) for iPod-specific development. Apps produced with the iPhone SDK are compatible only with the iOS on the iPod Touch and iPhone, which cannot run clickwheel-based games.

Question: What format is used for iPod game files?
Answer: .ipg

Question: What file format is being covered up by the use of ipg files?
Answer: .zip

Question: What does SDK stand for?
Answer: software development kit

Question: What is the only operating system on which iPhone SDK-made games can be played?
Answer: iOS

Question: What file format are iPod games distributed in?
Answer: .ipg

Question: An app produced with the iPhone SDK can only run on what devices?
Answer: iPod Touch and iPhone

Question: Is the Apple SDK available to third-party game publishers?
Answer: not