F3 PE is by far the best F3 (debug screen) mod. It looks almost identical to the debug screen in Minecraft for PC. It displays real time statistics for your player in-game which updates as soon something changes in-game (such as your coordinates or biome)
The debug screen is an existing feature in the PC version of Minecraft. It was never intended to remain but since players love it so much it has never been removed. Pocket Edition players will likely never see an official version of the debug screen, at least if you are to believe some of the latest Q & A livestreams with the developers. But it doesn’t matter much, since you can just use this mod to get it!
Update: This mod is based on Anti’s and peacestorm’s DebugPE mod. I didn’t realize this while posting this. But now you know!
Once you’ve installed the mod there will be a D (short for debug) in the top right area of the screen. Press the button to enable (or disable) the debug screen.
Here’s a brief explanation of each statistic displayed:
Author: MyNameIsAnti, peacestorm, Arthu25