"It’s also been a poorly kept secret for some time now that Apple has a set of its own advanced prototyping tools. Rumored to be called “Mica,” it’s a tool Apple created for its UI designers to craft interactive interfaces more easily. Mica is allegedly Quartz Composer’s internal replacement, and has been used to create everything from interfaces to Final Cut Pro plugins. I wouldn’t be surprised if Mica had a role to play in the creation of iOS 7 and 8."

The above quote is the best I could find for you. http://www.smashingmagazine.com/2014/09/19/prototyping-for-better-products-stronger-teams-and-happier-clients/

Hope this helps.

Cheers, BG