I am unwilling to accept an SDK's license in order to view my own data produced by my own hardware.

So, a couple years ago, I wrote a bash-wrapper [1] to Suto's perl FIT-parsing library [2]. With a quick search, I see that others may have extended Suto's work [3].

I'm pro-Garmin but can't understand hiding a measurement instrument's output format behind a closed-door license.

[1] https://github.com/4kbt/ParseVivosmartHR

[2] http://pub.ks-and-ks.ne.jp/cycling/GarminFIT.shtml

[3] https://github.com/mrihtar/Garmin-FIT