Your screenshots are a little bit strange …
If I switch to English my export panel looks:
Kurviger is not named Curvy and the index line looks different. As I said: strange!
And if one is using the Kurviger App for navigation he should use .kurviger files exclusively - period! The .gpx format is for Garmin-/TomTom-/whatever-Users. And for these devices additional waypoints are advantageous.