updated 02:42 pm EDT, Tue June 3, 2014
Function meant for recording app previews
The combination of iOS 8 and OS X Yosemite allows for easier screencapture of iOS devices, according to a new Apple document. In order to support the App Store's future App Previews, Apple has tweaked Yosemite to treat an iOS device as a camera input, meaning that any video recording software can be used to capture onscreen activity. Currently recording is described as "extremely laggy," but it will presumably improve as both iOS 8 and Yosemite get updated betas.
Capturing video is already technically possible with iOS devices, but requires a more complex setup involving AirPlay Mirroring, or an HDMI feed into capture equipment. Being able to record directly to a Mac may make it both cheaper and simpler for developers to produce promotional videos.