From the (somewhat lengthy!) Store description:
With this app you can view GPX files (routes, tracks, point of interest) on a Windows 10 pc. If you use a smartphone, you can also follow you and draw the route on the map, then save it in the device. THIS WAY YOU CAN RECORD A TRACK THROUGH YOUR SMARTPHONES, AND THEN VIEW IT ON YOUR PC LARGE SCREEN. You can import/export a local file (track route) in the documents folder of the device. You can also view a previously recorded GPX file or create a new one.
You have four modes of operation.
1) The first is a simple compass synchronized with map. You can disable this feature in the settings page "Synchronize map with compass (when follow or play is unactive)". If the option is checked the map rotate with you, otherwise the map is always facing north.
2) Follow me and draw route on the map. In the menu you must click on "Start follow me / Stop follow me". This feature is enabled when the option "Enable track route on map" in the settings menu is checked. When you stop the function clicking on "Stop follow me" , the route will be stored in the device. This way, if you go from point A to point B, you can record the route.
3) Follow me and don't draw route on the map. In the menu you must click on "Start follow me / Stop follow me". This feature is enabled when the option "Enable track route on map" in the settings menu is not checked. When you stop the function clicking on "Stop follow me", the route will not be stored in the device. This way, if you go from point B to point A, you can follow a route on map previously stored and loaded (follow back).
4) Replay route on the map (a route previously stored in step 2). In this way, when you are at home, you can replay a travel. Seeing the params as (course, speed, altitude).
It's an interesting use of both phone and PC, though you can also just use the former if you really want. So here are screenshots from Windows 10 Mobile:
You can grab 'GPX viewer and recorder' UWP in the Store here, it's a free download. Anyone going anywhere exciting where this might be useful?