What is the Apple GPS app supposed to do?

Hmm, interesting thanks. I can't find it in my purchases anywhere. It does looks a bit like the Navmii GPS phone app which I have but is not installed on my phone. However, that doesn't seem to have a watch version. I'll reinstall it and see if the watch one does anything

Ah found it - its MotionX-GPS. Its no longer available which is why I couldn't find it in the App store and the watch icon is somewhat different from the phone one which threw me when I was looking for it in purchases. While the phone app still works, some of its functionality went with the withdrawal of the app and I guess the watch functionality was one of them. I'll remove it (shame as the phone app is great and I still use it).

Thanks for your help :)

No its not Navmii so its not anything that appears in my purchase history