However, I followed in the footsteps of Lien, downloaded the iFruit app from iTunes, extracted the assets with 7Zip, ran the PNGs through FixPNG and then noticed exactly what Lien noticed: images and app assets for the PC version of GTA V.
The folder contains all the app's assets, including PNG images for the PS3, Xbox 360 and PC renditions of the GTA V manual. As an example, some of the files include a mention of a color wheel highlight bar for the Xbox 360, PS3 and PC (to avoid any legal heat I won't completely type out the name of the file, but if anyone bothers to look, you'll know what I mean).
More info: http://www.cinemablend.com/games/GTA-5-iFruit-App-Files-Confirm-GTA-5-PC-Assets-59178.html