Just do what you are told: In the datasource creation field, enter

GPX_USE_EXTENSIONS=YES

or check "surpress creation of attributes" underneath (or what it is named in your language).

In the layer creation field, you might also enter

FORCE_GPX_TRACK=YES

to get tracks instead of routes.

Just do what you are told: In the Data source field, enter

GPX_USE_EXTENSIONS=YES

or check "skip attribute creation" underneath (or what it is named in your language).

In the Layer field, you might also enter

FORCE_GPX_TRACK=YES

to get tracks instead of routes.