Getting Battery Health Information on iOS

Question

There are currently apps in the app-store (so it does not require jailbreak) that tell you :

1. Exact percentage value of battery level you have on your iPhone

Answer 1

It is likely that such apps use IOKit framework, which is public on OS X but private on iOS (it's not allowed by Apple to use private frameworks for App Store apps, although sometimes it can be overlooked during the review).

You can see a sample project here.