Works well on several of my GPSr - Just wish output to GPX files also! Will give 5-star when it does!
Hey Andy, sadly that is not possible with the current APIs, the only supported way of recording extra data is through FIT developer field extensions. Most CIQ devices don't even record GPX files natively, and when you export one from Connect the conversion from the FIT file happens server side, so I don't see that happening in the future.
I'm not even aware of an existing tool that does that so if you need that you'll have write your own. If it helps, the library I use for inspecting FIT files is this one: https://github.com/mrihtar/Garmin-FIT.git, and it's good enough to extract the data, including developer extensions.