On March 6, 2008 Apple released the very first iOS SDK allowing developers to build applications for iPhone.
This repo is a simple git client for iPhone built in 2013 using libgit2/objective-git library (Git Code on Appstore: https://itunes.apple.com/app/git-code/id680153559). Its source code released to Github on March 6, 2016 as a tribute to historic event by Apple.
It is fascinating to realize how dynamic iOS SDK is! In 2009 apps were developed with iOS SDK version 3. In 2013 this application was built using iOS 6 and later that year updated to iOS 7. Today, 2016 - iOS 9 and 10 are mainstream versions of iOS. All three SDKs - completely different worlds with different concepts and ideas.
Looking at 'Git Code' source code it is interesting to see how outdated it is comparing to current SDK. Not to mention that more and more code is written in completely new programming laguage - Swift.