GammaThingy – Open Source f.lux for your iPhone

Screen temperature is a public health feature which should be implemented by the OS. Until this feature arrives in iOS, the next best option is for apps to implement it. The ebook reader Marvin and Koala web browser both have controls for color temperature.

It's NOT open source as per the readme: "I purposely have not added an open source license to the project and am intentionally retaining copyright for the code, meaning that it may not be redistributed (in code or compiled form) without my permission."

So, what is it doing that f.lux isn't/can't on non-jailbroken phones? I know they'd need access to APIs that Apple doesn't make available.